(I'm not sure if it's a bug or it could be filed as suggestion.)

I'm trying to customize, via resource pack, the CB's torch. For example, I'd like to make a bigger torch head by editing torch_head_lit.png, which has two UV faces - one on the top middle, and another on the middle center -, I thought the 1st UV face was meant for the side faces, while the 2nd UV face was meant for the top face. It seems the 1st UV is unused; the torch block only uses the 2nd UV face.

torch_head_lit edited.

Unfortunately the size of the torch is hardcoded, along with UVs. Once I get the newer version out with the new json model system it would be easier to achieve what you want. It's still way early in development though.