Hello Warmwater, regards to all.
Just got back from Coz and I did both Dos Ojos and Batcave on the mainland. They are good cenotes to do. my last trip before this one I went to Puerto Morelos, up the road from Playa del Carmen, and I did the cenote called Chikin Ha, translated as "The Western Water." If I was to use a movie analogy, like Star Wars, Dos Ojos and Batcave are "The Force" and Chikin Ha would be the "Dark Side" which makes it more seductive and you want to go there. These cenotes can be checked through YouTube, just type the names and there are videos of them. Let me know how the search goes and which one you select! Diver Away!!!