Dunc, I would look over the conditions in images from competitions in various areas at:
http://fksa.org/forumdisplay.php?f=115
Jupiter and points north don't necessarily have to be really big but if a strong NE wind is on for a while, as happens in some fronts, you can have some big waves (head high to twice that + at times), and daunting shorebreaks to pass through. If you like wave sailing and are used to it, fun times are on. If not, may not be on. These conditions come and go over time. As you move south inside the lee of the Bahamian Plateau and as the reef system shallows, the large waves ease off. The shoreside population goes up of course at the same time. Off Pompano to Miami waves are usually broken up more, i.e. choppy in aspect but easier to get through within reasonable limits. From Biscayne Bay down through Key West, the fore reef and sheltered flats on the Straits side limit wave development near the Keys substantially, i.e. near flatwater conditions.
From all that you might want to find accommodations in Ft. Lauderdale to Deerfield, understanding that launches are tight here but it makes a great place to drive from. For the later part, perhaps you might want to stay down in the Keys, perhaps Key West. You could always drive down part of the way during the first part of your trip and form your own impressions. If you are willing to deal with slightly cooler conditions, there is a great deal more to Florida than the SE coast of course.