I've been there 4 times, May, July, October, November (4 different years); I've never seen a week with 20kts+ the entire week.
3 of mine were bareboat, the last was fully crewed. Of the bareboats the first 2 with Sunsail, third with Voyage; all catamarans so I can't help ya with boat selection. We did provision thru Sunsail the first time, and had the same missing stuff, substitution problem. Found out they use a local grocer (Bobbies, available online) so from then on just went to the grocer direct.
As to cab's, wouldn't know. I was on a boat - if I wanted to go somewhere I sailed there.
Moorings do indeed fill up early, planning where you are going and getting there are part of the fun to me. Besides, I don't drink unless tied to something so the earlier I caught a ball....
As to briefing's - they expect you to be knowledgeable about sailing/boat systems in general so the briefings are somewhat brief; if you feel the need for more perhaps you should hire a skipper for the first day, it runs about 150 bucks and depending on your resume they might require one.