Given that in actuality, it was applied free hand with an air gun, I think you have no options other than what you've proposed. Just keep the pressure very low (8-10 PSI) and the paint very thin. Keep regularly daubing the nozzle of your airbrush to clean out any build up.
You get a sense of what 1/72 aircraft builders must contend with on most builds!
I have a P-40 Medium almost done too. It'll have that same scheme you're using. Best of luck to you.
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