I'm going to have to second that motion.
IMO Block it now(lacquer primer) with 80 or 100 grit until you get as much lacquer primer off as possible. Then (what ever brand you decide to use) put on 2 coats of epoxy primer (seals it). Let that flash for a day (flash meaning let the solvents out). Most brand epoxies, don't need to be sanded before they are spayed over, with-in a week (or in some cases longer check the product specs).Then put 4 coats of 2K (urethane) primer. Block it with 120. Every time you sand it go back and spot "seal" it with epoxy on any sanded through spots. Put 3 more coats of 2K primer on it. Wait a good week. Then block it with 180. 2 coats of 2K. Wait another week. Block with 400. Soft pad Sand it with 600. And put on your paint. This should solve most of your possible shrinking problems. And should come out straight for your black. Sounds like over kill, but, Everytime you block and prime (properly) it will get straighter.
As for your paint choice, I say check out some of the newer (than Centari) products on the market. They are almost all easier to use and better finished products. As stated by others, I too would go with base/clear. The advantages are all over this forum. I'm sure that if you have used Centari in the past, with success, you'll rock with most any base/clear.
That'll be $.02