Do not use Testors primer! It dries slow and doesn't sand well, and is not compatible with many lacquers. The amount of pearl powder is up to you, but it doesn't take much. The best way to use it is to put your color down, let it dry, then mix your powder's in clear and spray over your color coat. Next, put a coat or two of straight clear over those coats to seal the powder, and get a better effect.
