So it's paint over foil? Airbrushed or hairy stick method.
Warren
Hairy stick, Sir, and one with very little hair. After the splotching, a good rub with a 3000 grit polishing pad (knocks away a good bit of the paint), then repeat the splotching and again the rub-down. Keeps it even and adds a certain extra randomness.
This is the machine it is intended to represent....

(I think the mottle is overwhelmed by glare, not absent, near the cockpit)