You dont ned a professional to mentor with. Many times I have dove with a club member or the like and after the dive some one says to another. Wow you looked good. How do you do that so effortlessly. Discussions lead to weighting ect adn the next dive you make changes and things are better. I mostly find that all I spire to be is not in a single diver, It is a gathering of the best of many divers abilities. Trim from one, kicking from another. buoy shooting from another. every one has something they are good at and few are good at as much as you want to learn. I have a guy I dive with occasionally that is still working on frog kicking, I am not good at it but he is not good at all. When he learns all he can from me then he will move on to someone else to improve from there till he is happy. Untill a few years ago i didnt care about trim. Now I do and though not an expert, I and others play hovering games and score by the silt stirred. Nothing but diving experience makes you better. One day i will be able to hover an inch off thesilt and shoot a buoy with no silt trace. But each to our own goals. Botttom line is that you dont have to buy a mentor. You do have to know what you want to become, who is better than you at it adn work to out do them. Most the time they will help you.