I live aboard and cruise
a 70j Hatteras MY with stabilizers and am currently based out of Miami. I spend most of my cruising days in the Bahamas, Keys and Cuba
. There are many day s I have sat at anchorage or marina before crossing the the gulfstream in either direction, and have had some very rough seas even in the Bahamas
--My boat is an "80 and is built like a tank, way too much fibreglass
It can take much more than the occupants. I'm am taking the boat to the Virgin Islands
in November. I'm not looking forward to most of the legs after leaving the Turks and Caico. I have made this trip before in a 55" sport fisherman and it was rough even waiting many days for good weather windows.
-- That said I would not attempt the trip in the boats you are looking at. First, the fuel issue-gas is vastly more expensive than diesel, much more difficult to find and gives you less range. Second, the boats you are talking about are not considered reasonable for blue water cruising-they are not made for the rigors and bashing into waves that will bury your bow deeply in even moderate conditions. Mine will be buried deeply regularly and will likely find a new leak point forward before I get to the Virgin islands.
-- I would look at a diesel powered boat that is larger and considered a decent blue water cruiser such as a Grand Banks
. If not power then look at some good blue water sail boats. Another option is to cruise the Bahamas and Keys for a while. Sell you gas powered boat in SE Florida
then find a nice diesel powered boat in St. Thomas or elsewhere n the Caribbean
. Once there cruising is much easier with short legs and many optons.
FWIW My two cents. Good luck to you.