Whichever ring height allows you to align your eye with the ocular lens when your achieve your natural cheek weld.
Secure the rifle. Use modeling clay rolled into two balls about an inch and a half in diameter. Place the balls on top of your receiver where the scope mounts and then place the scope on top of the balls. Establish your natural cheek weld and then press down on the scope until your eye is aligned with the ocular lens. Remove the scope, carefully remove the balls of clay and measure them at the center of the depression.
That measurement will be the height from the bottom of the tube to the top of the receiver that you should have. The actual height of your rings/bases will depend on whether you choose one piece rings, basses and rings or a rail and rings.
I have gotten to the point where I no longer try to guess what low, medium, high, xtra high actually means. I now find the rings/bases that I want and then email or call and tell them the distance from the bottom of the scope tube to the top of the receiver. They tell me what I need to order and I do.
I use Talley rings/bases on my bolt guns and Seekins or Era-Tac on my AR's.