I have been having the same trouble with the camo as well as the regular green uniforms. I think I have some close, but I use mainly Tamiya and Model Master's, can provide the colors I use however if you would like. The color I have found works best for the boondocker boots is Tamiya's XF-64 "Red Brown" or maybe you could use Model Master's leather. It sounds like you have found the right color for their regular green uniforms, I haven't used Vallejo before but I heard there was a color that was called "USMC WWII Fatigue green" is that an accurate color to use?