Robert Beverly Hale used the size of the cranium as the unit for measuring human proportions instead of the height of the head. This method is preferred by many artists because it aligns with skeletal landmarks and it is more reliable when actually drawing a figure in a pose.
Recently I had the pleasure of meeting Glenn Vilppu, a legendary instructor and artist. His teaching had a significant impact on my life and career. Mr. Vilppu and I had a conversation and I got to ask him some of the questions you guys submitted.