I actually have a usable scale for the head. I took crew into account when I made it. I have a few spare sentinel drivers, so I placed them in a mock-up of the head. There was still more than enough room for equipment, and body movement.
As for the shape of the head, I agree with you in a way, but this was easier to do, plus I just prefer the angular look, as that is what the rest of the model has.
I just wish that my camera picked up the detail a bit better. Oh well, it will come up better after painting.