Fuzzy - The 'Aircraft Colors' brand that I have been using of late are very good and easy to use. At least the camo colors, that is. I use them straight from the bottle in a gravity feed airbrush. Just yesterday I used the same brand to paint the yellow (RLM 04) banding on a German Dornier. Yellow as a rule does not cover well over darker colors, and so, neither did mine. After laying down a base coat of PollyScale white, and then painting the yellow, it came out very nicely, albeit a bit thick compared to the other colors. What I really like about the 'Aircraft Colors' brand is the eyedropper bottle that they come in. I can usually measure out just what I need into my airbrush with minimal waste.
To answer your specific questions, tip drying seems to be no different than any other water based (acrylic) paint. If I'm not spraying continuously, there will be some occasional clogging (tip drying), but I anticipate this, and I make sure to clear the gun before making my next passing spray. I spray at about 15 - 20 psi, but my gauge is really not that accurate, so I have developed a kind of 'feel' for the pressure by spraying air alone against the skin on my forearm. I don't know quite how to describe what feels 'right', so I also test the actual paint spray on a piece of paper or cardboard first.
I clean the gun by first filling the cup with Windex, shaking it up and wiping the inside of the cup with a paper towel. I then fill the cup with lacquer thinner, shake it up again, and spray that solution through the gun at a higher pressure (30lb. or so). Sometimes I will repeat the lacquer thinner process and jab the needle feed area with a small brush to loosen up some residue. Spraying one more cup full of lacquer thinner will complete it. Sounds like a lot of work, but it goes quite quickly.
I buy my lacquer thinner from Home Depot or Lowes. Costs about 9$ a gallon, and that gallon goes a long way compared to the 'airbrush thinners' from the hobby shops, but I use the cheap stuff for cleanup only.
Hope this helps.
Read through the forum, or do a forum search to find more info and techniques that others use.
Email me if you need more info.