How many materials for Buildings in an rts/td game

Hello, me and my friend are creating a mix of tower defense and rts game and want to make all the models ourself.

Iam just not quite sure how many materials i should use for a single building and what texture size it should be.

Because the camera is sitting further away from the buildings i dont need such high textures . I read that for rts games a texel density of 1,28px/cm or 2,56px/cm is common. But iam unable to achieve this texel density for a building with a max texture size of 2k . So should i use more materials for one house? i think i would propably like 2 or 3 materials to achieve the desired texel density i just dont know if its effiecient or if my uv unrapping just isnt that good. The Building also is fairly “complex” Screenshot - 82940667dd82b6c8a580de2c152c6f52 - Gyazo I just dont know if the complexity is enough to justify more then one material.