I've done some more research and head-scratching and come up with a custom mix of faded O.D. and ANA 613 that seems to have just about the right amount of khaki shading in it. It contrasts well enough with the medium green without being too light or too dark. This is a very hard nut to crack since I haven't any color photos of the Interceptor, just the black and white pictures. The various line drawings are very helpful but, again, the colors are somewhat of an educated guess.