try a agitator pot with flake( air cap will push it just get the right size ) in mix clear coat it will lay better and multi coats not too heavy it will sag then u can control density and wet sand in between after a few coats of clear good luck
Did a quick search and looked up a few things on metal flake. The absolute largest flake I could find was 0.125" (1/8" or 3mm). This is considered ridiculously huge and requires not a special tip but a special gun to spray.
If you look at the original wrap here at classic vintage drums,
http://www.classicvintagedrums.com/index.php?main_page=product_info&cPath=65_73&products_id=378
There is a good close up of the bass drum badge. I am guessing the bottom part of the letter "g" must be around 1/8". There is one of the larger squares of glitter right under the "g" MAYBE two thirds of the square is covered. That makes the larger squares approx 3/16" or 4.5mm. There is no way those large squares are being sprayed out of a gun.
Secondly, in the original post rogersfreek mentioned using glitter from a party store so I am going to go out on a limb and say the idea is to do this with supplies available to everyone at a reasonable cost. Finish booths, specialty guns, tips and tools, pre and post cat lacquer are not things that everyone has easy access to. I am going to try to keep it simple and limit myself to supplies from the party store and finishes available at the local hardware store and see how it goes. I'll try to post some pics in the next couple days.