According to the Emhar instructions, the basic colour is grey - FS16118. The colour chip of this looks like a Panzer grey - a dark grey - whereas Feld Grau is a greenish-grey.
Hundleby and Strasheim give the basic colour as German field grey (p167).
Presumably, this would indicate that the tank's basic colour has been repainted from the grey primer of the original paint when built?
I would have thought that a grey tank would have remained the original grey?
From what I understand about Field Grey, and it isn't much, it can be anywhere from a medium grey to a slate grey and even the greenish grey that is close to the uniform color. I think Panzer would be way too dark of a color for this period of time. I would use a greenish grey and keep all of the colors light. I hope this helps out and maybe someone with more knowledge then me can be more specific.
Regarding original colours, I think it was said in a thread some months ago that they were not - or might not have been - painted with primer, but were painted straight away in the Khaki-brown camouflage. If that's wrong, feel free to correct me. Certainly the tanks were designed and built for a short service life, so using primer may have been thought a waste of time, effort, and materials.
