Re: cheekweld
Its been said before above...#1 is you need a consistent cheek weld, well, actually you need perfect eye relief first - so in your case the need to adjust rings/scope may be critical. The cheek weld should be second nature (remember muscle memory comes from doing the action around 3000 times). With maintaining a cheek weld and not lifting the head off the rifle, you should be able to adjust parallax and dope, load your magazine, orient the magazine in the well (this seems "basic", but a lot of top comp. shooters will place a little strip of skateboard tape on the foreward end to know there will be no error), do a chamber round check, be able to clear malfunctions, and that keep that cheekweld consistently in the same place to catch splashes in absence of first round hits. Do not start the muscle memory process without being 100% sure your eye relief is perfect, and if you are one to change optics depending on the scenario, I have actually marked my rifle and rails with sharpie marker or white-out on where I need to place my rings and where I want that front objective to be so if I have to dissamble, or switch out scopes, I can go right back to where one scope should be versus the other without establishing the whole eye relief exercise again.
I personally don't "chipmunk", because I don't like feeling recoil in my molars where I had a bad root canal with higher caliber.
For those that feel they can't hold a cheek weld well for hours because of sweat (esp. in the summer) and its critical to your line of work (you know who you are), please feel free to contact me to send you sample of an item than may help.