BW and U3MA File Size

How much of a given BW file's size is generally be allocated to the texture maps?

It is a 1:1 ratio. So, if you put in 40MB of textures you add 40MB to the file size. We compress our assets, but images are usually already compressed so the compression doesn't make a huge differences.

Does the size of a U3MA file directly translate to the portion of the BW file that is allocated to the fabric?

Same as the preceding question: it is a 1:1 ratio. So, if you have 3 material files at 10MB each, they account for 30MB in the BW file.