I guess it all depends on the conditions. If waves are pounding the shore, you will have a hard time hooking up. I will put it this way. I was down there for a week with my wife. I fished most mornings, most evenings and went trolling three times (30 min each). So I definitely didn't go hard everyday. In those 7 days I went 2/8. I had more than one fish on per day on average. I just happened to lose a lot of fish this time for some reason.
As far as pressure goes, I would argue that Cuba, particularly Cayo Coco and Cayo Santa Maria, receive very low pressure compared to some other places like Florida. The locals rarely fish with lures so that fish are not savy to them like in other places. Hence, I would most definitely consider going down there for an actually fishing trip. Especially between May and September.