Dave,
If you dive St Croix stop by and talked to Big Ed of stcroixscuba.com. He runs a great operation and tell him that John from SCUBA "U" sent you. You can also send him an e-mail before you go down and ask him anything that you can think of before you get down there.
As for a wetsuit, I always recommend one on every dive.
We have a store located in Burbank, IL if you would like to check out any suits or any other equipment. Stop by or give us a call at 708-599-2630 even if it just to ask some question you may have.
Thanks
John
SCUBA "U"