spray guns aside...
when i shoot any high metallics, i criss-cross my color coats to lessen stripes or 'cornrows.' i spray med wet coats, moving the gun somewhat fast...not real fast. i tack off each coat with a basecoat tack rag. on the last coat, [say 4th coat] i lower my air to 30 lbs & increase my gun distance to maybe 12".....careful not to create stripes. i let the color dry around a 1/2 hr @ 70 degrees. re-tack the base & start spraying the clear.
don't psyche yourself out...base metallics aren't bad.
"Never argue with an idiot. They'll drag you down to their level and beat you with experience." Alfred E. Newman