This is great information ... but what I was asking ... poorly.  Is how do they relate to each other as far as the figure goes (Obviously for the Generation 4 Daz figures).  The face is how many times bigger than the torso while the torso is how many times different than the limbs.  All in relation to each other.  That ratio?

I don't know how precise this needs to be...  But using power of two textures you could use a 512x512 map for the face, a 1024x1024 map for the limbs, and a 2048x2048 map for the torso.  I am assuming you are worried that there will be an obvious seam where the different resolutions meet?  In that case I'd also look into adding a slight procedural noise/grain bump to all three, as those are resolution independent.