After a lot of research, we now believe this beautiful Dark Green is actually the rear colour on the ESB Joe Johnson painted Fett helmets, we believe it was mixed with Engine Black, much like the Darker Red on the Face. It seems to be a roughly 50/50 Mix of Dark Green and Engine black for a perfect match to the long unknown Fett Helmet Colour. The same (mixed) colour is also used on the cheeks of one of the touring helmets.
To be thinned with Archive-X AX-ATR thinner for airbrush use. Ratio's vary from colour to colour with an average of 70/30 paint to thinner.