As I understand it, the process phantom3D is working on does not add geometry, it swaps it and welds it in place. Because the clothing geometry uses the same rig, and usually will have less polys, it does not use more resources (except the space to store the insertion poses and geometry on the hard disk).

It seems to me that the real problem will be in applying MAT poses. Poser does not seem to handle partial MAT poses very well. With conforming cloths this is not a problem, because the clothing is a separate figure. When the clothing is part of the same figure, it will take some ingenuity to change the MAT of the clothing, without changing the MAT of the skin.

lmk

Probably edited for spelling, grammer, punctuation, or typos.