That's really interesting stuff...I've never metal-flaked using anything besides my paint guns.
These pics are of a bike that I painted and shipped the tins back to him in Finland. The flake is Lil Daddy Roth "Warm Beer" .015" flake. I sprayed it through my well-cleaned-out primer gun in order to: (a) take advantage of the larger spray tip and (b) so I would not get freakin' flake all through the next job that I clearcoated!
I just mix up a regular 2:1 reduction of HOK SG100 intercoat clear, dump in the flake, and keep "swirling" the gun around to keep the flake suspended in the clearcoat and not all settle right to the bottom of the paint cup!
This flake laid down pretty decent and I blieve I used either 2 or 3 separate 3-coat applications/wet-sandings of HOK UC35 Kosmic Klear to make it smooth as glass.
Just another option... and I have no idea whether the Monster Flake (.025") would flow through a primer gun because I've never tried it!