Wow. Are you sure this is your first mask paintup? I have a hard time believing that you haven't done this already. You must be a natural at it. Or, maybe you know a lot more about color theory and layering than I'll ever hope to learn.
That's a great first attempt with the airbrush! I recently borrowed a friend's airbrush to attempt a similar project on a Star Wars mask I'm making and I really can't get the hang of using the airbrush....it's a lot tougher than it looks!