Getting them over their head-shyness will be very helpful whenever things come up like a bad shed, an injury, or illness.

With Caesar, I would get him comfortable in my hands, and then very slowly slide my fingers along his body, toward his head, until I can touch and gently grasp. Not only does this teach him that I won't hurt his head, it also teaches me how to properly handle him, should I ever need to for the reasons mentioned above.