I'm 5'9", really thin, and the thighs on every model ever made don't fit me. What I usually end up doing is seeing if I can either edit the model, or make strategic cuts in the sides/back, so that I can pull it to be a tighter fit around my leg. On the Reach thighs, there's that thinner part on the inner bottom that can be cut without messing up the rest of the piece too much. And if you're really into modding it, you could cut strips out of the piece and just try to paper scratch build it into being smaller. It just takes a lot of messing around, mostly. However, that could be more difficult with your method of not doing any surface finishing, but I hope that helps.