I've tried a few coaches and I've come to the conclusion that most of them, and I suspect most strong chess players, don't really know why they are strong.
They know a lot of 'book' stuff; positional play, openings, end games, strategies and tactics. But they cannot really tell you how this stuff is coming together in their heads or how you can utilize it the way they did. Even Magnus Carlsen(as far as I've seen) has never been able to give any solid ideas about how he is able to do what he can do.
Therefore, they seem to just feed you the same 'book' stuff they learned thinking that is what you need.
I think if you want to find a good teacher, you should find one that has written some of their own material BASED ON THEIR OWN THINKING TECHNIQUES or at least a unique interpertation of the thinking techniques of stronger players.
ALso, I would like to say it may not be a good idea to limit your self to GM's. Your rating is low enough that if you can find any good teacher with a title, you will learn enough to progress.