Thought I'd add my 2 cents, I've made this trip 6 times and my next will be in April. I have taken the north route around Cuba any time from January through August. I have been to Cuba 7 times, the last being in November. The reality is that more likely than not if you want to stop in at Hemingway Marina in Havana nothing ill will come of it. There are Americans living full time there with out any problems. The crossing over from Florida will most likely be short choppy seas(4-6) feet. From the west side of Cuba hugging the coast it's a short hop(approx. 50 miles) to Cancun. I've only ever made this crossing once that the seas were 3 feet or possibly less. Staying about 10-15 miles off Cuba will keep you out of the current while you are heading west. A
spinnaker will help save on
fuel since you are in the most northerly Trade Winds. No book learning here just been there and done that (a lot). Since this is my back yard, I'm quite familiar with it. After all they cross the Atlantic in an open rowboat. Hope this helps.