Well, consider me flattered...
I've found for smooth drybrushing that a soft brush is the way forward, and like for all things, slightly thinned paints.
I'm diggin' the turqoise base for brass and copper, it seems to take away a bit of the shine and give an oxidised look to it.
Believe it or not, the hot water pipe coming out of our boiler was my colour study for this. *wink*