Make sure you put a big bait on a heavy rod down near the bottom when you are fishing the reef also. Could be a pinfish, ballyhoo, or whatever. You never know what is going to show up to inspect your chum slick.
Last time I was down we chummed along the reef and caught all the yellowtail you wanted. I switched to jigging a 1 oz. head with a BKD and caught grouper, triggerfish and several others I could not ID while the others chummed. Heading down to Marathon in late May for a week with my brother in law and siister. They go every year in may and do great on dolphin, have caught several between 40 and 50lbs casting to grass mats. The fish out of a 22' Pathfinder so they can't be going too far.