Re: Bottom paint
Regarding your keel blasting and refinishing, I'd recommend you review Joel's "classic" post #2960 (and 2964 and 2116). (Just type the number in the "Msg #" box above.)
Plus you could review this Petit Technical Bulletin specifying only one coat of Rustlok, followed within 1/2 to 2 hours by three coats of Petit High Build Epoxy Primer, then fairing as needed with 7050 EZ Fair, then two coats of antifouling with a Petit product.
Note the Technical Bulletin does not call for any barrier coat, because, of course, this is cast iron, not fiberglass.
Joel's posts advise to stick to one manufacturer's system, so if you start with Petit, stay with Petit. And the key to all is to get the first coat (Rustlok) applied within minutes after sandblasting.
Good luck with the project - and thanks for arranging the new rub rails - I'm picking mine up tomorrow.
Craig -- SN68 Sangaris, Tropic Isle Harbor, FL