With pronunciation, if one hasn't practiced enough, s/he won't be able to truly understand and master those rules. And I guessed that is why although many people know this "back mouth" theory, even the best teachers are not able to give an instance solution to solve the learner's problem immediately.
Here are some personal experiences. I have been working with algorithms for many many years. When I play with the algorithms in my field, mostly I can play artfully (after so many years of studying and practice).
With English pronunciation, after 1 year's practice, right now I honestly think I know what this "back mouth" pronunciation is and how it works. But I am far from speaking English beautifully/artfully although I always thought I had a little talent in language.
I am also learning dancing starting nearly a year ago. Since it has very low priority on my weekly schedule and I seldom practice it after class, my teacher says I am doing mechanics. He is actually being nice and not wanting to scare me away, for I clearly know that I am not yet doing the correct and accurate mechanics (I feel my English pronunciation is somewhat close to such a mechanically correct stage -- though far from artful).
When being asked what I need to do and how should I do it to dance as beautifully as he does, my teacher says, "practice! I dance 20-30 hours per week, while you do only one hour a week. Not to mention the years I started ahead of you!" This guy is a multi-time national award winner and one of the best teachers I ever know. For every detail I'm not able to do well, he has a solution to improve/correct it. But currently I am still not able to even get close to there. Hopefully in 10 years, I may get out of the mechanistic stage in dancing.
Hope this lengthy writing explains a little on how practice helps the learners to get the essence of any kinds of arts. (My theory: mostly, theories work only through pratice.)