Yes, St. Pete is fine - I have sailed Davis Island a couple of times.
My only regrets are that I love sailing in the keys - I guess the clear water. Also it seems like a lot more work to organize our own regatta versus piggy backing off the 18hts. If we don't want a 5 day regatta, I am sure we could run 2 or 3 down in the keys. For me I would drive the extra 3 hours to take what is being offered.
That said I am not as hard pressed as I make out to be, and I'll look forward to doing it at either location.
Chuck
PS Are you getting 5 boats our at one time often? If you have any races a group is planning attending, let me know - every so often I can sneak away