So, without furthern ado here's Simon's colour guide:
The different shades of khaki on some trousers, blouses and caps represent pieces from different origins, delivery batches and also some, that haven been in use longer than others and therefore faded under the Manchurian sun.
I basically used 4 colours: GW Foundation Khemri Brown and Dheneb Stone and Vallejo Game Color Desert Yellow and Bonewhite.
The darker coloured uniforms used a base of Khemri Brown highlighted with Desert Yellow and finally a little Bonewhite. The lighter uniforms were given a base mix of Khemri Brown and Dheneb Stone, with more Dheneb Stone being used for highlights (I may have added a little white for some of the final highlights as well).
The differences may seem a little bit extreme but I've actually seen worse fading and colour variations during my own mandatory military service in 2002/03.