Finally, PAINT LOL ;D
I'm 100% with MJ regarding the pre shading.
I did my base coat with a mix of tamya deck tan and white. It was ok but I was not totally satisfied with it. Some filters using heavily thinned oils (different greys, blue, some ochre) corrected that. What I learned: don't go crazy trying to find that perfect paint mix, just make sure you don't go too dark. Afterwards you can always tweak things to your liking, I call it manual photoshop ;D
Cheers