you might want to give 123d Catch a try as well to photo digitize a head and have a 3D model to provide dimensional boundaries. I found real 3D scans or 3D models a lot more helpful to match face details the best.
not too bad. I have seen these blue prints in use before and the only problem I ever have with them is that the posture is a bit un-natural but rigging the model can easily fix this problem. looking good so far, keep up the good work.