Thanks to everyone for their very good advice. As always, this hobby will find new ways to inhale any extra monies I might have had. So now I'm looking at a 10mm hood, Fourth Element glove liners (I use Diving Concept dry gloves, like them much better than DUI), and the Thermalution vest. Like Allison, I'd rather go that route than add extra bulk and extra lead. As it is, I can barely climb back in the boat.
Allison, thanks very much for the information. Since we know you wear one size smaller than I do :-), what size is your vest?