Exterior house latex is great for painting warbirds. I would experiment with flat and semi gloss to decide which I prefer. No priming is needed for painting over fiberglass. I would not use an airbrush if I were you. I tried my airbrush for some detail work and the latex dries too fast and plugs up the air brush. I use a Binks auto touch up gun to spray the latex. I started thinning it with auto windshield fluid like the article you mentioned, but I found distilled water worked just as well, sometimes better.

You will like the latex, it goes on easy, dries fast, and is incredibly durable. Your local Sherwin Williams paint store can match any color you bring them, at least they did for me.

Email if you have any questions
Vince