Well, I can type out the way to mask it.
Basically, you mask like usual, but spray the color you want the pinstripe to be first. Then lay a strip of fineline down just inside the tape of the outside of your flames. Follow it exactly, or the pinstripe will be wavy and inconsistent widths. Now spray the color of your flames. Remove ALL the tape and clear as you normally would. This leaves a nice clean edge all the way around.
As far as fading from one color to the next, the way I do it it by spraying the lightest color first. Then I start on the opposite end of where I want the fade to start and paint towards the edge of the fade. I usually mark the area I want to fade with a piece of tape. I have two pieces of it, where I want to start fading and where I want it to stop. I just try to "fan" the gun at the first piece and let it dust to the last. I go progressively further each time till I get the look I am after.
