which one of these areas would someone recommend to snorkel and to be able to lay around on the beach? thanks for the info, also has anyone ever snorkeled cemetary reef at grand cayman?

In my experiences in Cozumel, both have good snorkeling. Chankanaab is usually more crowded since that is where they have the dolphin discovery. Dzul Ha has excellent snorkeling and is usually less crowded than Chankanaab. I found a lot of good info on the cozumelinsider.com website.