Greg, your situation sounds so much like mine few years ago that it is scary.
I tried it for awhile but never could master it. Finally decided to stop fighting it and switched to the dominant side....... Best thing I ever did for my consistency. I used to have the occasional arrow that missed it's mark by several feet just as you described. After switching to the dominant eye....it has never happened....ever. Problem solved, with nothing extra to think about. Squinting even slighly, messed with my vision too much to be acceptable to me. And this unnatural action must be repeated each time to ensure maximum accuracy.
Those unpredictable large misses screw with your confidence....and the thought of wounded game caused me to explore a more permanent and natural option.
You really won't believe the improvement in your sight picture until you try it. Also, try shooting at a candle or similar in total darkness. I almost guarantee that you are not shooting purely instinctive. If you were, your right eye wouldn't be trying to align the arrow....causing your far right misses. Good luck man, it's a tough road either way.