I played around a bit and managed to glaze multiple objects at once, if that's useful to anyone. Figured since crafts are made in batches, they might as well be glazed in batches too.
Here are the reactions for multiglazing crafts:
[REACTION:GLAZE_CRAFT_ASH]
[NAME:ash glaze clay/stone craft]
[BUILDING:KILN:CUSTOM_CTRL_A]
[REAGENT:glaze:15:POWDER_MISC:NONE:NONE:NONE][REACTION_CLASS:GLAZE_ASH]
[REAGENT:glaze container:1:NONE:NONE:NONE:NONE][CONTAINS:glaze][PRESERVE_REAGENT][DOES_NOT_DETERMINE_PRODUCT_AMOUNT]
[REAGENT:craftA:1:ANY_CRAFT:NONE:NONE:NONE]
[REACTION_CLASS:CAN_GLAZE]
[EMPTY]
[NOT_IMPROVED]
[PRESERVE_REAGENT]
[REAGENT:craftB:1:ANY_CRAFT:NONE:NONE:NONE]
[REACTION_CLASS:CAN_GLAZE]
[EMPTY]
[NOT_IMPROVED]
[PRESERVE_REAGENT]
[REAGENT:craftC:1:ANY_CRAFT:NONE:NONE:NONE]
[REACTION_CLASS:CAN_GLAZE]
[EMPTY]
[NOT_IMPROVED]
[PRESERVE_REAGENT]
[IMPROVEMENT:100:craftA:GLAZED:GET_MATERIAL_FROM_REAGENT:glaze:NONE]
[IMPROVEMENT:100:craftB:GLAZED:GET_MATERIAL_FROM_REAGENT:glaze:NONE]
[IMPROVEMENT:100:craftC:GLAZED:GET_MATERIAL_FROM_REAGENT:glaze:NONE]
[FUEL]
[SKILL:GLAZING]
[REACTION:GLAZE_CRAFT]
[NAME:monochrome glaze clay/stone craft]
[BUILDING:KILN:CUSTOM_CTRL_G]
[REAGENT:glaze:30:POWDER_MISC:NONE:NONE:NONE][REACTION_CLASS:GLAZE]
[REAGENT:glaze container:1:NONE:NONE:NONE:NONE][CONTAINS:glaze][PRESERVE_REAGENT][DOES_NOT_DETERMINE_PRODUCT_AMOUNT]
[REAGENT:craftA:1:ANY_CRAFT:NONE:NONE:NONE]
[REACTION_CLASS:CAN_GLAZE]
[EMPTY]
[NOT_IMPROVED]
[PRESERVE_REAGENT]
[REAGENT:craftB:1:ANY_CRAFT:NONE:NONE:NONE]
[REACTION_CLASS:CAN_GLAZE]
[EMPTY]
[NOT_IMPROVED]
[PRESERVE_REAGENT]
[REAGENT:craftC:1:ANY_CRAFT:NONE:NONE:NONE]
[REACTION_CLASS:CAN_GLAZE]
[EMPTY]
[NOT_IMPROVED]
[PRESERVE_REAGENT]
[IMPROVEMENT:100:craftA:GLAZED:GET_MATERIAL_FROM_REAGENT:glaze:NONE]
[IMPROVEMENT:100:craftB:GLAZED:GET_MATERIAL_FROM_REAGENT:glaze:NONE]
[IMPROVEMENT:100:craftC:GLAZED:GET_MATERIAL_FROM_REAGENT:glaze:NONE]
[FUEL]
[SKILL:GLAZING]
[REACTION:GLAZE_CRAFT_DICHROME]
[NAME:dichrome glaze clay/stone craft]
[BUILDING:KILN:CUSTOM_CTRL_D]
[REAGENT:glaze:15:POWDER_MISC:NONE:NONE:NONE][REACTION_CLASS:GLAZE_NOT_WHITE]
[REAGENT:glaze container:1:NONE:NONE:NONE:NONE][CONTAINS:glaze][PRESERVE_REAGENT][DOES_NOT_DETERMINE_PRODUCT_AMOUNT]
[REAGENT:white glaze:15:POWDER_MISC:NONE:NONE:NONE][REACTION_CLASS:GLAZE_WHITE]
[REAGENT:white glaze container:1:NONE:NONE:NONE:NONE][CONTAINS:white glaze][PRESERVE_REAGENT][DOES_NOT_DETERMINE_PRODUCT_AMOUNT]
[REAGENT:craftA:1:ANY_CRAFT:NONE:NONE:NONE]
[REACTION_CLASS:CAN_GLAZE]
[EMPTY]
[NOT_IMPROVED]
[PRESERVE_REAGENT]
[REAGENT:craftB:1:ANY_CRAFT:NONE:NONE:NONE]
[REACTION_CLASS:CAN_GLAZE]
[EMPTY]
[NOT_IMPROVED]
[PRESERVE_REAGENT]
[REAGENT:craftC:1:ANY_CRAFT:NONE:NONE:NONE]
[REACTION_CLASS:CAN_GLAZE]
[EMPTY]
[NOT_IMPROVED]
[PRESERVE_REAGENT]
[IMPROVEMENT:100:craftA:GLAZED:GET_MATERIAL_FROM_REAGENT:glaze:NONE]
[IMPROVEMENT:100:craftA:GLAZED:GET_MATERIAL_FROM_REAGENT:white glaze:NONE]
[IMPROVEMENT:15:craftA:BANDS:GET_MATERIAL_FROM_REAGENT:glaze:NONE]
[IMPROVEMENT:100:craftB:GLAZED:GET_MATERIAL_FROM_REAGENT:glaze:NONE]
[IMPROVEMENT:100:craftB:GLAZED:GET_MATERIAL_FROM_REAGENT:white glaze:NONE]
[IMPROVEMENT:15:craftB:BANDS:GET_MATERIAL_FROM_REAGENT:glaze:NONE]
[IMPROVEMENT:100:craftC:GLAZED:GET_MATERIAL_FROM_REAGENT:glaze:NONE]
[IMPROVEMENT:100:craftC:GLAZED:GET_MATERIAL_FROM_REAGENT:white glaze:NONE]
[IMPROVEMENT:15:craftC:BANDS:GET_MATERIAL_FROM_REAGENT:glaze:NONE]
[FUEL]
[SKILL:GLAZING]
[REACTION:GLAZE_CRAFT_POLYCHROME]
[NAME:polychrome glaze clay/stone craft]
[BUILDING:KILN:CUSTOM_CTRL_R]
[REAGENT:red glaze:15:POWDER_MISC:NONE:NONE:NONE][REACTION_CLASS:GLAZE_RED]
[REAGENT:red glaze container:1:NONE:NONE:NONE:NONE][CONTAINS:red glaze][PRESERVE_REAGENT][DOES_NOT_DETERMINE_PRODUCT_AMOUNT]
[REAGENT:blue glaze:15:POWDER_MISC:NONE:NONE:NONE][REACTION_CLASS:GLAZE_BLUE]
[REAGENT:blue glaze container:1:NONE:NONE:NONE:NONE][CONTAINS:blue glaze][PRESERVE_REAGENT][DOES_NOT_DETERMINE_PRODUCT_AMOUNT]
[REAGENT:yellow glaze:15:POWDER_MISC:NONE:NONE:NONE][REACTION_CLASS:GLAZE_YELLOW]
[REAGENT:yellow glaze container:1:NONE:NONE:NONE:NONE][CONTAINS:yellow glaze][PRESERVE_REAGENT][DOES_NOT_DETERMINE_PRODUCT_AMOUNT]
[REAGENT:white glaze:15:POWDER_MISC:NONE:NONE:NONE][REACTION_CLASS:GLAZE_WHITE]
[REAGENT:white glaze container:1:NONE:NONE:NONE:NONE][CONTAINS:white glaze][PRESERVE_REAGENT][DOES_NOT_DETERMINE_PRODUCT_AMOUNT]
[REAGENT:craftA:1:ANY_CRAFT:NONE:NONE:NONE]
[REACTION_CLASS:CAN_GLAZE]
[EMPTY]
[NOT_IMPROVED]
[PRESERVE_REAGENT]
[REAGENT:craftB:1:ANY_CRAFT:NONE:NONE:NONE]
[REACTION_CLASS:CAN_GLAZE]
[EMPTY]
[NOT_IMPROVED]
[PRESERVE_REAGENT]
[REAGENT:craftC:1:ANY_CRAFT:NONE:NONE:NONE]
[REACTION_CLASS:CAN_GLAZE]
[EMPTY]
[NOT_IMPROVED]
[PRESERVE_REAGENT]
[IMPROVEMENT:100:craftA:GLAZED:GET_MATERIAL_FROM_REAGENT:blue glaze:NONE]
[IMPROVEMENT:100:craftA:GLAZED:GET_MATERIAL_FROM_REAGENT:red glaze:NONE]
[IMPROVEMENT:100:craftA:GLAZED:GET_MATERIAL_FROM_REAGENT:yellow glaze:NONE]
[IMPROVEMENT:100:craftA:GLAZED:GET_MATERIAL_FROM_REAGENT:white glaze:NONE]
[IMPROVEMENT:35:craftA:BANDS:GET_MATERIAL_FROM_REAGENT:blue glaze:NONE]
[IMPROVEMENT:35:craftA:BANDS:GET_MATERIAL_FROM_REAGENT:red glaze:NONE]
[IMPROVEMENT:35:craftA:BANDS:GET_MATERIAL_FROM_REAGENT:yellow glaze:NONE]
[IMPROVEMENT:100:craftB:GLAZED:GET_MATERIAL_FROM_REAGENT:blue glaze:NONE]
[IMPROVEMENT:100:craftB:GLAZED:GET_MATERIAL_FROM_REAGENT:red glaze:NONE]
[IMPROVEMENT:100:craftB:GLAZED:GET_MATERIAL_FROM_REAGENT:yellow glaze:NONE]
[IMPROVEMENT:100:craftB:GLAZED:GET_MATERIAL_FROM_REAGENT:white glaze:NONE]
[IMPROVEMENT:35:craftB:BANDS:GET_MATERIAL_FROM_REAGENT:blue glaze:NONE]
[IMPROVEMENT:35:craftB:BANDS:GET_MATERIAL_FROM_REAGENT:red glaze:NONE]
[IMPROVEMENT:35:craftB:BANDS:GET_MATERIAL_FROM_REAGENT:yellow glaze:NONE]
[IMPROVEMENT:100:craftC:GLAZED:GET_MATERIAL_FROM_REAGENT:blue glaze:NONE]
[IMPROVEMENT:100:craftC:GLAZED:GET_MATERIAL_FROM_REAGENT:red glaze:NONE]
[IMPROVEMENT:100:craftC:GLAZED:GET_MATERIAL_FROM_REAGENT:yellow glaze:NONE]
[IMPROVEMENT:100:craftC:GLAZED:GET_MATERIAL_FROM_REAGENT:white glaze:NONE]
[IMPROVEMENT:35:craftC:BANDS:GET_MATERIAL_FROM_REAGENT:blue glaze:NONE]
[IMPROVEMENT:35:craftC:BANDS:GET_MATERIAL_FROM_REAGENT:red glaze:NONE]
[IMPROVEMENT:35:craftC:BANDS:GET_MATERIAL_FROM_REAGENT:yellow glaze:NONE]
[FUEL]
[SKILL:GLAZING]
And just for the heck of it, I slapped reactions together to glaze bricks and hives, since it bugged me that the vanilla raws let you make clay ones but not glaze them. The letters used are kind of random, I've been meaning to go through and set it up so there's no overlaps.
[REACTION:GLAZE_BRICK_ASH]
[NAME:ash glaze clay/stone brick]
[BUILDING:KILN:CUSTOM_W]
[REAGENT:glaze:15:POWDER_MISC:NONE:NONE:NONE][REACTION_CLASS:GLAZE_ASH]
[REAGENT:glaze container:1:NONE:NONE:NONE:NONE][CONTAINS:glaze]
[PRESERVE_REAGENT][DOES_NOT_DETERMINE_PRODUCT_AMOUNT]
[REAGENT:brick:1:BLOCKS:NONE:NONE:NONE]
[REACTION_CLASS:CAN_GLAZE]
[EMPTY]
[NOT_IMPROVED]
[PRESERVE_REAGENT]
[IMPROVEMENT:100:brick:GLAZED:GET_MATERIAL_FROM_REAGENT:glaze:NONE]
[FUEL]
[SKILL:GLAZING]
[REACTION:GLAZE_BRICK]
[NAME:monochrome glaze clay/stone slab]
[BUILDING:KILN:CUSTOM_Y]
[REAGENT:glaze:30:POWDER_MISC:NONE:NONE:NONE][REACTION_CLASS:GLAZE]
[REAGENT:glaze container:1:NONE:NONE:NONE:NONE][CONTAINS:glaze]
[PRESERVE_REAGENT][DOES_NOT_DETERMINE_PRODUCT_AMOUNT]
[REAGENT:brick:1:BLOCKS:NONE:NONE:NONE]
[REACTION_CLASS:CAN_GLAZE]
[EMPTY]
[NOT_IMPROVED]
[PRESERVE_REAGENT]
[IMPROVEMENT:100:slab:GLAZED:GET_MATERIAL_FROM_REAGENT:glaze:NONE]
[FUEL]
[SKILL:GLAZING]
[REACTION:GLAZE_BRICK_DICHROME]
[NAME:dichrome glaze clay/stone brick]
[BUILDING:KILN:CUSTOM_SHIFT_Z]
[REAGENT:glaze:15:POWDER_MISC:NONE:NONE:NONE][REACTION_CLASS:GLAZE_NOT_WHITE]
[REAGENT:glaze container:1:NONE:NONE:NONE:NONE][CONTAINS:glaze]
[PRESERVE_REAGENT][DOES_NOT_DETERMINE_PRODUCT_AMOUNT]
[REAGENT:white glaze:15:POWDER_MISC:NONE:NONE:NONE][REACTION_CLASS:GLAZE_WHITE]
[REAGENT:white glaze container:1:NONE:NONE:NONE:NONE][CONTAINS:white glaze]
[PRESERVE_REAGENT][DOES_NOT_DETERMINE_PRODUCT_AMOUNT]
[REAGENT:brick:1:BLOCKS:NONE:NONE:NONE]
[REACTION_CLASS:CAN_GLAZE]
[EMPTY]
[NOT_IMPROVED]
[PRESERVE_REAGENT]
[IMPROVEMENT:100:brick:GLAZED:GET_MATERIAL_FROM_REAGENT:glaze:NONE]
[IMPROVEMENT:100:brick:GLAZED:GET_MATERIAL_FROM_REAGENT:white glaze:NONE]
[IMPROVEMENT:15:brick:BANDS:GET_MATERIAL_FROM_REAGENT:glaze:NONE]
[FUEL]
[SKILL:GLAZING]
[REACTION:GLAZE_BRICK_POLYCHROME]
[NAME:polychrome glaze clay/stone brick]
[BUILDING:KILN:CUSTOM_ALT_X]
[REAGENT:red glaze:15:POWDER_MISC:NONE:NONE:NONE][REACTION_CLASS:GLAZE_RED]
[REAGENT:red glaze container:1:NONE:NONE:NONE:NONE][CONTAINS:red glaze]
[PRESERVE_REAGENT][DOES_NOT_DETERMINE_PRODUCT_AMOUNT]
[REAGENT:blue glaze:15:POWDER_MISC:NONE:NONE:NONE][REACTION_CLASS:GLAZE_BLUE]
[REAGENT:blue glaze container:1:NONE:NONE:NONE:NONE][CONTAINS:blue glaze]
[PRESERVE_REAGENT][DOES_NOT_DETERMINE_PRODUCT_AMOUNT]
[REAGENT:yellow glaze:15:POWDER_MISC:NONE:NONE:NONE][REACTION_CLASS:GLAZE_YELLOW]
[REAGENT:yellow glaze container:1:NONE:NONE:NONE:NONE][CONTAINS:yellow
glaze][PRESERVE_REAGENT][DOES_NOT_DETERMINE_PRODUCT_AMOUNT]
[REAGENT:white glaze:15:POWDER_MISC:NONE:NONE:NONE][REACTION_CLASS:GLAZE_WHITE]
[REAGENT:white glaze container:1:NONE:NONE:NONE:NONE][CONTAINS:white glaze]
[PRESERVE_REAGENT][DOES_NOT_DETERMINE_PRODUCT_AMOUNT]
[REAGENT:brick:1:BLOCKS:NONE:NONE:NONE]
[REACTION_CLASS:CAN_GLAZE]
[EMPTY]
[NOT_IMPROVED]
[PRESERVE_REAGENT]
[IMPROVEMENT:100:brick:GLAZED:GET_MATERIAL_FROM_REAGENT:blue glaze:NONE]
[IMPROVEMENT:100:brick:GLAZED:GET_MATERIAL_FROM_REAGENT:red glaze:NONE]
[IMPROVEMENT:100:brick:GLAZED:GET_MATERIAL_FROM_REAGENT:yellow glaze:NONE]
[IMPROVEMENT:100:brick:GLAZED:GET_MATERIAL_FROM_REAGENT:white glaze:NONE]
[IMPROVEMENT:35:brick:BANDS:GET_MATERIAL_FROM_REAGENT:blue glaze:NONE]
[IMPROVEMENT:35:brick:BANDS:GET_MATERIAL_FROM_REAGENT:red glaze:NONE]
[IMPROVEMENT:35:brick:BANDS:GET_MATERIAL_FROM_REAGENT:yellow glaze:NONE]
[FUEL]
[SKILL:GLAZING]
[REACTION:GLAZE_HIVE_ASH]
[NAME:ash glaze clay/stone hive]
[BUILDING:KILN:CUSTOM_T]
[REAGENT:glaze:15:POWDER_MISC:NONE:NONE:NONE][REACTION_CLASS:GLAZE_ASH]
[REAGENT:glaze container:1:NONE:NONE:NONE:NONE][CONTAINS:glaze]
[PRESERVE_REAGENT][DOES_NOT_DETERMINE_PRODUCT_AMOUNT]
[REAGENT:hive:1:TOOL:ITEM_TOOL_HIVE:NONE:NONE]
[REACTION_CLASS:CAN_GLAZE]
[EMPTY]
[NOT_IMPROVED]
[PRESERVE_REAGENT]
[IMPROVEMENT:100:hive:GLAZED:GET_MATERIAL_FROM_REAGENT:glaze:NONE]
[FUEL]
[SKILL:GLAZING]
[REACTION:GLAZE_HIVE]
[NAME:monochrome glaze clay/stone hive]
[BUILDING:KILN:CUSTOM_U]
[REAGENT:glaze:30:POWDER_MISC:NONE:NONE:NONE][REACTION_CLASS:GLAZE]
[REAGENT:glaze container:1:NONE:NONE:NONE:NONE][CONTAINS:glaze]
[PRESERVE_REAGENT][DOES_NOT_DETERMINE_PRODUCT_AMOUNT]
[REAGENT:hive:1:TOOL:ITEM_TOOL_HIVE:NONE:NONE]
[REACTION_CLASS:CAN_GLAZE]
[EMPTY]
[NOT_IMPROVED]
[PRESERVE_REAGENT]
[IMPROVEMENT:100:hive:GLAZED:GET_MATERIAL_FROM_REAGENT:glaze:NONE]
[FUEL]
[SKILL:GLAZING]
[REACTION:GLAZE_HIVE_DICHROME]
[NAME:dichrome glaze clay/stone slab]
[BUILDING:KILN:CUSTOM_SHIFT_V]
[REAGENT:glaze:15:POWDER_MISC:NONE:NONE:NONE][REACTION_CLASS:GLAZE_NOT_WHITE]
[REAGENT:glaze container:1:NONE:NONE:NONE:NONE][CONTAINS:glaze]
[PRESERVE_REAGENT][DOES_NOT_DETERMINE_PRODUCT_AMOUNT]
[REAGENT:white glaze:15:POWDER_MISC:NONE:NONE:NONE][REACTION_CLASS:GLAZE_WHITE]
[REAGENT:white glaze container:1:NONE:NONE:NONE:NONE][CONTAINS:white glaze]
[PRESERVE_REAGENT][DOES_NOT_DETERMINE_PRODUCT_AMOUNT]
[REAGENT:hive:1:TOOL:ITEM_TOOL_HIVE:NONE:NONE]
[REACTION_CLASS:CAN_GLAZE]
[EMPTY]
[NOT_IMPROVED]
[PRESERVE_REAGENT]
[IMPROVEMENT:100:hive:GLAZED:GET_MATERIAL_FROM_REAGENT:glaze:NONE]
[IMPROVEMENT:100:hive:GLAZED:GET_MATERIAL_FROM_REAGENT:white glaze:NONE]
[IMPROVEMENT:15:hive:BANDS:GET_MATERIAL_FROM_REAGENT:glaze:NONE]
[FUEL]
[SKILL:GLAZING]
[REACTION:GLAZE_HIVE_POLYCHROME]
[NAME:polychrome glaze clay/stone slab]
[BUILDING:KILN:CUSTOM_ALT_B]
[REAGENT:red glaze:15:POWDER_MISC:NONE:NONE:NONE][REACTION_CLASS:GLAZE_RED]
[REAGENT:red glaze container:1:NONE:NONE:NONE:NONE][CONTAINS:red glaze]
[PRESERVE_REAGENT][DOES_NOT_DETERMINE_PRODUCT_AMOUNT]
[REAGENT:blue glaze:15:POWDER_MISC:NONE:NONE:NONE][REACTION_CLASS:GLAZE_BLUE]
[REAGENT:blue glaze container:1:NONE:NONE:NONE:NONE][CONTAINS:blue glaze]
[PRESERVE_REAGENT][DOES_NOT_DETERMINE_PRODUCT_AMOUNT]
[REAGENT:yellow glaze:15:POWDER_MISC:NONE:NONE:NONE][REACTION_CLASS:GLAZE_YELLOW]
[REAGENT:yellow glaze container:1:NONE:NONE:NONE:NONE][CONTAINS:yellow
glaze][PRESERVE_REAGENT][DOES_NOT_DETERMINE_PRODUCT_AMOUNT]
[REAGENT:white glaze:15:POWDER_MISC:NONE:NONE:NONE][REACTION_CLASS:GLAZE_WHITE]
[REAGENT:white glaze container:1:NONE:NONE:NONE:NONE][CONTAINS:white glaze]
[PRESERVE_REAGENT][DOES_NOT_DETERMINE_PRODUCT_AMOUNT]
[REAGENT:hive:1:TOOL:ITEM_TOOL_HIVE:NONE:NONE]
[REACTION_CLASS:CAN_GLAZE]
[EMPTY]
[NOT_IMPROVED]
[PRESERVE_REAGENT]
[IMPROVEMENT:100:hive:GLAZED:GET_MATERIAL_FROM_REAGENT:blue glaze:NONE]
[IMPROVEMENT:100:hive:GLAZED:GET_MATERIAL_FROM_REAGENT:red glaze:NONE]
[IMPROVEMENT:100:hive:GLAZED:GET_MATERIAL_FROM_REAGENT:yellow glaze:NONE]
[IMPROVEMENT:100:hive:GLAZED:GET_MATERIAL_FROM_REAGENT:white glaze:NONE]
[IMPROVEMENT:35:hive:BANDS:GET_MATERIAL_FROM_REAGENT:blue glaze:NONE]
[IMPROVEMENT:35:hive:BANDS:GET_MATERIAL_FROM_REAGENT:red glaze:NONE]
[IMPROVEMENT:35:hive:BANDS:GET_MATERIAL_FROM_REAGENT:yellow glaze:NONE]
[FUEL]
[SKILL:GLAZING]