I've also produced over 50 different "body types". Since these models had to work retroactively on ALL existing content, there were several requirements:

-UV Layout had to match the previous model which was essentially a series of cube primitives.

-The joint locations (shoulders, torso top, torso bottom, legs, feet, hands) MUST be at specific points to match the existing rig. This would allow "gear" assets to sit convincingly within model's hands and on its body. (EX: 1st of image catalog is the layout and rig system that I followed)

All "Body" Models are:

Poly Count <1500 tris
Max res. 1024 px, with only 1 Diffuse channel (Alphas accepted for clothing underlays)