To complete my skull, there were three extremely helpful actions. The first was to make a few broad adjustments based on the photos from my last post. After looking at the images and retaking some measurements, I realized I needed to actually remove some mass, not continue to add as I had been. This was especially helpful for the chin and jaws.
The second helpful thing was Richard's feedback about using the clay to "draw" on the form in an almost exaggerated way and then refining, removing, and reshaping the additions. This was particularly helpful with the eyes, temples, and cheekbones.
The last thing was looking at the model skulls in close proximity to my work. It was much easier to compare angles and negative space when I could put them side-by-side. Additionally, I had both skulls next to me for a few minutes, and this helped me to see which parts of the skull seemed more like a "rule" and where there might be a little more flexibility. I found this helped a great deal with the cheekbones, jaw, and teeth.
Areas to Improve
I believe my skull is still a bit lopsided. Perhaps this could have been fixed if I had more time to dedicated to it.
Additionally, its surface is quite irregular. I am still not as comfortable with the tools, including the paddle, as I probably ought to be. I don't know if I am simply unskilled with them and so I don't trust them, or if the novelty of the tactility of a new medium is too enjoyable for me to bother with tools. I will admit to be a bit infatuation with the marks fingers leave on the clay.
The proportions of the skull are still not perfect, and part of it is a bit thick and clunky where I think it perhaps should have been rendered more delicately.
Who looks more like death?
The main issue at this point is simply that everything on the front of the face needs moved down. Second to that, the top of the skull needs a bit of attention, as its current shape gives the impression that the face is slowly sliding off the front of the head. The jaw will also need addressed aggressively, although since the lower half of the face is so new, this is not surprising and a lower priority.
Applying the rule of thirds seemed redundant since I just compared my skull to my actual head, but moving the eyes and nose down in this photo does immediately help it to look more human (although still bizarrely narrow. I keep measuring, but it keeps being SO NARROW!)
However, something about this skull still doesn't feel right -- aside from its lack of width. I have always been aware that my forehead is perhaps a bit large and wanted to see if the rough rule of thirds was actually what needed applied here.