We've been going to Cuba for twenty years, usually diving on the south side except a couple of times when doing the bull shark dives in Santa Lucia. Wife and I have never dove in Veradero because we were told its not the best diving in Cuba, plus we prefer more remote places on the island. But others who have been there have told us there is good diving there. We've found in Cuba its usually OK to show up the day of the dive, but we always go to the shop the first day we arrive and introduce ourselves, providing we took an earlier flight. We had some great dives in Cuba and love the island and the people, even if the government leaves a bit to be desired..
Enjoy Cuba as it was. Once the embargo ends it will become an entirely different place.