here you go john, just part of a reply that i had during my aer lingus repaint. after finding out the hard way about the vents.
If you are using the earliest C-47 model for this paint i.e. the BEA aircraft, which I think you are, then the bad news is that those vents are not textured, if I recall. This problem was sorted later with the subsequent C-47 models. Could you use one of those? You're not going to have any seats in there whichever model base you choose, but the latter would cover your problem. It's not really noticeable with the typical white or bare metal top, but your green shows the vents up, of course.
When my dear BETSY finally gets released, she will have C-47 doors AND seats in one of her (eight) model iterations. Soon, I hope... I just never have time to play .
so once it is released then the flood gates will open. until then your stuck with the cargo or passenger version. so i keep on learning to paint on the only canvas i have.
