This is a really cool looking model!, and I'd be hard pressed to say it wasn't a production kit. You did an excellent job of creating and fabbing (is that a word?) all of the custom parts... which it sounds like was most of them.
Interesting experience with the decals... I've got several of the Aviattic decals but only one sheet each (4, 5, upper and lowers) of the printed on white stock. That may be the way to go in the future? (my only experience with them to date, printed on clear, has been to test them out on a Roden Fokker D.VI upper wing. As the wing was molded in white I just painted on some PFG and applied... the jury is still out but probably similar to your experience, the color on the edges seem to be wearing away with handling).
What's next... Sablatnig N.I ? ? ?
Take care
Scott...