Hey Westcat, I'm contemplating this class also. I live a few hours down the coast, near Morro Bay. We windsurf quite a bit here, and the 5.0 sail is a good average size for a typical, moderately windy (20 kts) day.
The idea that someone can depower a sail *that* large is pretty impressive (not to mention use a spinnaker in 20+ kts!), but one wonders what happens when we view the problem from the other (dark?) side, that of the windsurfer who carries a set of 3-5 sails around and rigs the right one for a given day. If you're a light crew and sail most of the time offshore in California, how about just using smaller sails most of the time? It certainly seems legal under the class rules...or have I read them correctly?