Also, if you're going to spray metallics or pearls, make sure you read up on the different spraying methods, as if you try spraying them normal you'll get what they call train tracks.
It's not as obvious on a small surface like a guitar as it is on a car, but it's still good to do the research and cover bases.
I was taught the following tip by a mate of mine who is a member of this forum but I don't think he posts, just lurks. He used to paint trucks for a living and I'm pretty sure I remember him saying some of the paints he used were as much as $2000.00 a liter! So they have to get it right the first time. Spraying a massive surface like a truck you need to have a technique down or it'll look like arse
When I spray these type paints I usually spray 3 coats.
First I spray normal horizontal. Second I spray diagonal left to right. Third I spray diagonal right to left.
On the second layer you'll still see train tracks, then on the third it'll just fill and look "right"
When you mix it up like this all the flake spreads even and looks great. If you shoot it normal then you run the risk of areas not being even.