Oh so much confusion on the last two pages, you should have just waited for me
3.xx branch of TWBT acts just like vanilla when it comes to tile size, limits, etc. so you have min. 80 columns limit and can't use large tiles on small screens. (The purpose of 80 column limit is quite understandable, you can't support any screen size on all game screens, so there should be some limit anyway, 80 is a standard).
4.xx branch of TWBT allows to use any tile size, no more min. 80 columns limit. By default tile size will match the size of the main graphics font (it means creature graphics and additional tilesets loaded for overrides will be resized to match it).
But there's a command "twbt tilesize <w> <h>" that will resize any tileset to any size.
Oh yes there also commands "twbt tilesize smaller|bigger" that you can bind to shortcuts to zoom in and out.
Although version 3.xx is included in LNPs, I recommend to use 4.xx. There are no known major issues with it, and if there are I'd rather fix them and discontinue 3.xx branch.