I too have found love for Vallejo Model Air !! Instead of distilled water ( for Me th distilled water seems to dry it out a bit too much ) I'll add some of Their Thinner to th mix, but very little as th Model Air is thinned already. Depending on psi & how tight of a pattern you wanna shoot, will determine how thin you want it. At least that's what I've found works for Me.
When I go to shoot a German Tri-Tone I'll start with Vallejo's Dark Yellow Primer as a base coat & hight light/fade with a mix of Dark Yellow + German Camo Beige + thinner . For Green I'll use Their Model Air Dark Green & Highlight th same with a touch of German Camo Beige. Their Model Air Tank Brown gets th call for th Red-Brown , again highlighting a mix of German Camo Beige.
Now with all of this you may find that you get a lil' build up of paint on th tip of th needle. That's why I keep a #0 brush handy & dip it into some Distilled Water & brush over th tip when it get's a lil' bit of build up on it & then you are clear & ready for take off !!
Here's a shot of a Tiger that I recently painted , just to give ya a picture of what I'm talkin' about
WHAT DO YOU CALL THE ASSASSINS THAT ACCUSE THE ASSASSIN???