You can use the hat to develop muscle memory and that could improve your anchor. It could very well be a useful tool.
My anchor is middle finger to corner of my mouth, index finger to bottom edge of my nose and thumb knuckle to the jawbone at the bottom of my ear lobe. I know that sounds like alot of points, but it is just all in the way you hold your hand and it ensures that you come to full draw. You get a consistant relase this way also.
I have a friend that shoots so well that everyone else at the tournament is shooting for 2nd at best. He hunts better than he shoots also. He told me this kind of anchoring would help improve groups and he was right. Ya just gotta listen to the pros!!