Okay. What are nubs? Well, I don't know what else to call 'em. Nubs are made of Magic-Sculpt and are platforms for the jaw's axle tube-ends to rest upon.
In the photo, the one on the left is the top-side where the tube will rest. The one on the right shows the bottom side. The sharp edge will be sunk into a small glob of Magic-Sculpt on each side of the head's interior. The solid nubs will be moved around in the soft Magic-Sculpt until the jaw finds its proper free-swinging position. The globs of Magic-Sculpt will dry and secure the nubs in place.
Nubs. Easy to make. No baking required.