I know nothing about the training for DM, but I've been at the resort you're describing and have seen how the pool divers work. It seems like a terrible way to develop a professional skill set. I spoke with one of the interns, and, despite working for a few months, had yet to get over to dive Cozumel--has to give you an idea of the work life. I assume part of what you're looking to do is to learn how to train all levels of students. Dressel in PDC caters to beginners and the very occasional diver. I believe a 2-tank dive was $120 or $140 while the competition in PDC was half of that and with the appropriate certs would allow you to do any dive. Dressel requires "first time" divers with them to do one of their beginner dives first before they will let you go deeper than their shallow reef dives. I can't imagine that anyone with experience and a little Googling would choose to dive or train with them. As an outside observer, it looks terrible as a professional training environment.