I use Vallejo Russian Green exclusively for my braille scale Russian AFV builds.
To lighten I use a drop of yellow ochre to the base colur and fade out panels. Progressive fading is achieved by adding a little more yellow ochre.
Once a brown filter is added, plus dot filters and pin washes (all oils), the colours darken and look quite effective.
The Trumpeter 1:72 KV-1's and UM BA-6 are a good example of what I am saying.
and Dragon's T34-76 model 1940, taken with my new camera gives a better example.
I hope that helps answer your question.