Good to hear from you! It looks as though you've escaped New England for warmer parts.
Sounds as tho Roger has answered your questions about the sails, and he's good at that, but I have used the boom end flotation device.
I've got pro and con thoughts on the boom end flotation for waterstarts, and I've heard much the same from people I know who have them. They do help to float the boom end, and are most useful, in my opinion, for sails with camber inducers, and in places with a lot of current, and in fresh water where none of us float as well, including the gear.
On the other hand, they restrict your ability to adjust the outhaul, it's one more thing to put on and take off every time you rig, and they don't really help you to learn to fly the sail efficiently for a good waterstart. If you are in shallower waters with not much current, I'd save the money for a sail.
The device is a great idea, depending on what the circumstances are.