Looks like you've got a project with potential, and it doesn't even look bad as a "before".
Everything I've painted has had some horrid orange peel if I didn't wet sand every color and clear coat, but not much of it has been metallic (and all of it has been rattle can)..The stuff I painted my side covers and will eventually paint my tank with has a metallic base, Shimrins Kandys..white metallic base, then a semi-translucent color (apple red for mine), then the clear. The side covers turned out fairly well, I haven't painted the tank yet, but I'm figuring I might do it this summer at some point when I'm working on somthing else on the bike..maybe polishing all the aluminum a bit better.