Right now, it looks as if my best option for acrylics is to paint for 10 to 20 minutes, then do a complete tear-down and cleaning on the airbrush. With enamels and lacquers, it seems to be enough to run lacquer thinner through the airbrush between colors.
I've also been advised that my Harbor Freight Central Pneumatic AB may be contributing to the difficulty I'm having. Other information suggests that the Central Pneumatic AB is not necessarily bad, but at best it's merely good. I have no prior experience with ABs for comparison.
But I've got some good looking Alclad sprayed on the chromie bits and I managed to get a satisfactory shade of green for the body using rattle cans.
It all works out in the end. And if it doesn't, it's only plastic, grab another kit and try something different.
Thanks for the input,
David G.