I mixed a lighter green from Vallejo Model Air Russian Green (71.017) and Vallejo Model Air White (71.001), approximately 60:40, green to white. This was sprayed over the entire upper hull and turret trying not to get it into areas where there would be natural shadows. The road wheels were also lightly misted.
I then added more white to this mix and sprayed those areas that would receive the most natural light, such as the turret roof, hull and fuel tank tops, and the upper sides of the turret and hull.
I'm not sure if I mentioned before that I drilled out the lightening holes on both the drive and idler wheels. Even at this scale, I think it enhances the look. Here's a shot, before and after, of one of the drive wheels: