When I sprayed my truck (white) I used Nason BC/CC. Sprayed the base, taped off the flames and shot the blue pearl mixed into the clear coat as a carryer. Untaped, then buried everything in the clear topcoat. These flames are very hard to see and the light has to be directly on them. I call them "Stealth Flames".
You can see them better on the lid.
In order to make them more visible you should probably go with a candy blue. Do a few test panels to get the coverage you need for the look you want.
I would also suggest doing the paint job and laying one or two light coats of clear on the base, to seal it up, before taping and shooting the flames. This will give you some time to get your flames laid out and masked. Once you get the flames sprayed, unmask, knock done the edges and then shoot your pearl white. You should then shoot a couple of heavy coats of straight clear just so you have something to wetsand and polish without getting into the pearl.
You may also want to check out this site.
They have some very cool pearls and candies and the stuff is very inexpsensive...