Instead of doing the "Wedge Method" you could just carve the head out of a solid chunk of foam thats anywhere from 8 1/2"-11" square, and save yourself from a lot of work. Get an electric drill, a 3M rotary disc sanding pad which mounts in the chuck of the drill, some sanding disc pad sheets, 50 grit grade. Then take your foam, trace the shape out that you want on it, facing the front of the head first, then cut that out with a hacksaw blade. (If you dont have a bandsaw this will work fine.) Then trace out your profile and cut that out. Cut off the excess edges, then round out the head with the rotary sander and you're good to go!