Here's some images that may help you in the right typr of colors.
http://www.missing-lynx.com/gallery/german/sdkfz251c_boehler.html
I used the gass cans and the color type from this model to do my Sd.Kfz 251/17.
I just mix some testors colors till go got close to what I thought was right. now Testors has a paint kit out for just this type of project, Called Camo Coloers. The Amo box nex to the white jar, Image 2 the box open.
Good luck and I can wate to see your build.