You'll be fine shooting a metallic.
The key to a good metallic basecoat/ clearcoat paint job is to keep a tac cloth and some 800 paper handy.
Basecoat sets up in about 15 min to tac off and nib any odd pieces, to re-base.
The key to getting a metallic to look good is to forget medium coats. Go on with normal pressure and flow, but back the gun off of the surface until you're about 15" away or so. About a foot to a foot and a half, depending on how it's pattern looks.
Not sure? Hit a piece of masking paper with it first. I shoot for full coverage on the 5th coat... I just did a House of Kolor Zenith Gold that took 13 coats to cover... Just don't rush the base. Ignore gloss and coverage per pass on the gun. Just pay attention to the pattern. Start looking for color coverage after the 3rd coat.
If you go over it with the intention of 3-5 coats on that color, it will cover evenly. Silvers and golds take more, because it's just the metallic flakes giving coverage with minimal pigment. Banding has more to do with distance than angle, but both are good to keep monitoring. The key is to not even try to get full coverage on each pass and let multiple coats gain coverage. If it looks covered, dust it again with a medium-light coat and see if you can tell any difference. Get in the booth with a flashlight and look for dry areas on lower facing body lines in the color. It's also nice to check for clearcoat coverage with a flashlight.
Also, keep the gun moving relatively quick. This helps minimize patterns and aids in gaining even coverage over more coats.
Single stage metallics are the tricky ones. You have to treat that like an acrylic enamel and do a light tac coat first, to get it to stick, do light coats and treat it the same, then hit it with one good medium coat to finish it for gloss, or the metallics can move too much.
Base/ Clear is so much easier to work with. If something gets weird during color, you can always let it sit 30 min and cut it out, tac cloth then tac coat that area and follow up with base until it blends out in a few coats.
Just shoot it. You'll be fine. If you'd like any other pointers, feel free to PM me. I'm working on a base/ clear Surf Turquoise '66 D100 short bed pickup paint job right now at my shop.