i been pretty lucky and played lots of pros, mostly just as a rack boy while they are getting warmed up for something. Depending on the circumstance I sometimes ask for a little help, other times I only rack and watch or in SVB's case I just watch him do his thing sitting 5" from the table

I dont stay and watch him the whole time but come in and out while he is playing-he never stops playing, he works harder than any other player I Have ever seen, bar none!!!)
Max Eberly and Charlie Williams have helped me the most, They put the most effort into helping me. Tang Hoa helped me alot as well.
I have learned a few tricks from Corey Deuel, I have never played him but been around him and he shared a little of what he knows, he might know about pool than anyone. Look at at Donny Mills his friend-I'm certain that he has helped him a lot. I never really asked Corey for anything I was just in the right place at the right times. I have talked to him about many other things outside of pool and he is a very very smart guy. When it comes to science and things along those lines he is like talking to National Geographic. I believe thats why he is such a great player he took what he knows and put it to use in pool, I didnt. I have since I met him and thats helped my game. So indirectly Corey has helped me and I dont know if I have ever played him-I dont think I have.
JA is the best player I have spent any time with, and I have spent lots of time with him, mostly racking for him. I asked him for some help and he didnt have much to say to me. He has helped me with the mental aspect of pool-but my point here is JA is so good he dosent know how good he is and its hard for him to be a instructor for players that know all the basics, he is a great instructor for the pool schools they have done. But at my level he dosent really help me much as Charlie Williams can. Charlie is a better instructor for me, personalities also come into it as well. Whats good for one student might not be right for the other. CW is a drill Sargent go go go .... JA is more passive and relaxed.
So the point is its a good teacher isnt defined by his speed. JA is a player, thats it-he does one thing better than anyone. CW can play, teach etc. Max is a artist, teacher, player etc. Everyone has differnt skills in life and having a high gear dosent mean your a better teacher.
I dont know Earl good enough to comment, other than I was very happy to see him win a big tournment recently. And I know that he is a good teacher cause he has students when ever he wants to teach and have heard good things here about him.