So, the proposition is to remove MINOR_METAL and METAL_PREF (maybe keep the latter for backwards compatibility) and add [MAX_METAL:] and [MIN_METAL:] tags, specifying exactly which metals a race will usually use. The values fed to these would be the maximum and minimum effectiveness percentages (DAMAGE_PERC and BLOCK_PERC) that a metal must have for the race to use it.