hmm whys the top guide bowed upward as the other is straight? and face purportions may help. try making a circle, half that and put a line, for the eye line, then the bottom portion, half that for where the nose ends, then under that take the upper 3rd of that for the lip line. let the lines bend with the sphere, heads not flat
http://cellosoft.com/2draw/view/85557/