Don't worry about pigment size; that's not the issue. The issue is laying down a thin coat of paint. I don't use enamels, but I can do this with MM acrylics. I haven't tried it with any of the gloss Acryls.
When I say 'thin coat', I'm not talking about paint consistency, but about the thickness of the coating. I have better results spraying a few _very_ light coats of paint (some might call these mist coats). If I try to cover in one coat, it is invariably too thick.
Chris