Small update. Started modeling the inside of the nostrils and adding some definition to the face. The model has become more male in the process of resculpting the nose and mouth area with extra curves. The loft is also holding up pretty well considering that the control point count on the curves has become irregular and the control points don't line up horizontally as they did before. I'm using the "loose" option with points set to "auto".

btw, this is the first time I've modeled a head using NURBs, ever. I'm kind of excited that its working OK so far.