White, especially in small areas, is a real pain! Painting the spinner on my Mustang is holding up the whole job, as it's white, and doing the ususl streak/lump/bump etc. All I can suggest is to build up thin or fine coats, preferably with the airbrush. But! If it's for the AEAF stripes, I wouldn't be too concerned about the overall surface finish, as even those stripes which were applied meticulously weren't perfect when viewed close up, due to the type of washable, temporary 'paint' used.
If you're really having great problems, then try laying a base coat of matt white, then, when totally dry, one or two coats (if needed) of gloss white.