i set my rings as far apart as they can be set with a chassis so that eliminates the scope needing to be moved forward or back then make all the other adjustments with the butt stock...you should be able to mount your rifle set your cheek open your eyes and be in the eye box or very close. when you make your adjustments make sure you are in a comfortable relaxed position and then you need to repeat that position the next time you shoot...if your position changes your going to think or feel like your LOP or other adjustments are not right so it may be partly your not mounting the rifle the same way each time.

for the eye issue...this worked well for me....i would set up and before i fired a round i would lay behind my rifle with both eyes open for 5-10mins every time id go out(and still do)and while waiting for the barrel i will lay there and look through the scope...i timed myself a couple of weeks ago and i can look through my scope for 20mins before i start having issues.

you need to find a happy medium with your adjustments and practice.