Since you're wanting to use an air brush, I don't know that this will be much help, but the auto parts stores carry DupliColor touch up paints..... I use the stuff almost exclusively and get fair results. Only bad thing is it kinda limits color choices. They make several primers, (I use black sandable for almost everything), then you use the Perfect Match cans for color and clear with the Perfect Match clear...... That's how I painted this model...... The clear can be polished after it's dried for a couple days......
Hope this is some help.............