Seems interesting and lots of cool collabos (Post Imeprial, Beams, Tunue de Nimes, etc.)
Most probably a size 40. Aero jackets fit slightly large, particularly through the shoulders and upper back. If you are pretty angular in the shoulders, you can get away with a size larger. I personally usually take a size 38 in that Type III jacket. I do not have angular shoulders, and so there is a lot of extra room in the back of the shoulders, especially, if I size up. It's a compromise, since this means that the chest is sorta tight for a very good fit through the shoulders, but I figured that for a Type III jacket, who ever does up the buttons anyway?
Agreed, thank you for getting me one! I'll PM you my shipping address :)