The Caribbean - Need some diving guidance for Caribbean cruise

Hello all... My wife and I (certified divers) will be taking a Windstar Caribbean cruise in February. The cruise makes 6 port stops, and we'd like to dive at 1 or 2 of them.
Ports include:
- St. John
- St. Maarten
- St. Barts
- Tortola
- Jost Van Dyke
- Virgin Gorda

So, here's the 2-part question.
1. If you could pick 1-2 of these destinations for a dive, which would it be?
2. Once we narrow down where we'll want to dive, I presume it would be best to pre-book the dives (including transportation from the ship). So, any recommended dive operators would be appreciated.

Thanks.

I don't have much knowledge of diving in all your ports of call but for sure you should experience St. Maarten (check to see if there is a dive excursion to Saba). Guarantee you will find the diving breathe taking - no pun intended.

Another great dive experience is Great Tobago just a short boat ride off Jost Van Dyke where you will find extraordinary and advanced dive sites, and a marine sanctuary.

Good luck