When I printed this I had some trouble with the supports under the jaw. I put solid bases on them, instead of the points they started on. I also put a version with the supports with points at the bottom if you want less clean up.
You want to print this full size so you have deep enough pockets for your pens. I made as much space as I could inside the skull, without affecting the outer appearance.
I used two processes in Simplify. The first for the base I used infill of 10% and a resolution of .3 mm. At 27 mm, I switched to an infill of 15% at .2 mm.