My number one rule on my anchor point is, for my anchor to be comfortable. Never try to force an anchor point, nothing good will come from it.
It seems most anchor problems come from too heavy of a bow. You should be able to draw your bow until your back muscles will not allow any more pull and be able to hold the anchor. I am not saying that to be a good shot that one needs to hold at anchor for 10 seconds, but if the situation arises you should at least be able to hold a solid anchor.
Try drawing your bow to anchor while your eyes are closed a few times, you will end up at a comfortable anchor. Once you figure out what is good for you and your shooting, try to figure out at least two different anchor points. You can use any finger on a top tooth or face bone, feather on your nose, string on your eye brow, thumb joint on your jaw. Well you get the picture, use what works for you and will produce positive results. Good luck, it will come together