I was considering a skipping over this message again because your question is one that kinda hurts because I want to provide you with answers and, for a couple of reasons, can't. It will eventually be in a forthcoming book, but who knows when that will be. Been having deal after deal fall through since going out of business in 1997.
If and when I ever do get back into publishing billiard books again, books on fundamentals will not be among the first few printed. Though they happen to be the ones I consider most needed, they will almost certainly be several times tougher to get done. That's mainly because it will go so much against a great many agreed-upon things that will require so much more in the way of explanations, which is mainly because it is so much harder to teach students who are already quite convinced about less workable tech.
There is something I can do that may help you somewhat. My advice is to not be at all concerned about which is your dominant eye! I won't go into detail on the subject but I hope you'll trust that I do know what I’m talking about. I know what you may now be thinking; but that is what so many teach! However, I can't help what others teach.
As for understanding why, that would take more than just a little bit of explaining, probably a couple pages would do it. A guy named Bob Fancher once wrote a paper about the subject of dominant eye that largely supports what I've just told ya. You can probably search the internet for Bob Fancher and then find what he has written on that particular subject.
My personal opinion is that even he doesn't really, fully understand the "whys" behind the subject of dominant eyes, but he certainly explained a lot about results of various tests.
Hope you'll simply trust me on this one,
Eddie Robin