I have a custom Paul Wilson stock on my 77 springer which has a very high cheekpiece area.
I decided ( rightly or wrongly ) to let the weight of my head rest against the cheekpiece naturally and zero at that.
I did that because I presume that the key thing is having the same pressure every time. If I have to conciously try and push harder than natural or try and put a lighter pressure than natural then it will be difficult to get the same pressure everytime, as there will be face/neck muscles pulling, whereas just letting the natural weight rest reduces muscle use/tension.
Does that make sense?
Height wise my stock has a fixed very high cheekpiece. So I had to slide cheek up and down with natural weight until eye lined up with scope.