This is the problem in a nutshell - the Double 12 has no 24hr hand to point at the outer scale, so the 24h bezel would have no function.Glycine has made many modern Airmans, in 36mm, 38mm, 39mm, 42mm, and 46mm. But the Double 12 is the first (I believe) in 40mm. The closest would be the Airman 8 which is now 39mm. So probably no swap would fit physically. Not sure how a switch would work functionally anyway, since the Double 12 is a regular three handed 12 hour watch and the other Airman bezels are all 24. Do you plan on replacing the movement with a 2893 and making it into a 12/GMT watch?