Great build!
Not that you asked, but if I were you I would leave the red oxide, but weather the heck out of it. Make up a heavy concentration of ink/alcohol and go at it. Follow up with black chalk. You could end up with an almost-black structure that still shows hints of a long-ago coat of red. I think that approach would honor the spirit (if not the letter) of your prototype very well, and give your model a lot of character.
