HI, I would have to say that just about any color combination would do during this period. Either the dark yellow for the base or even just the red primer with spots or designs, or even stripes of either red-brown, Pz. Green or even the Pz. yellow. The tank itself could be painted one combination of colors and the barrel left in the red primer too.
Knowing the Germans I'm sure there would have to be some 'offical' code that was to be used, but to say that it would be followed would be just dreaming. Let your own judgement be your guide here and I don't think whatever you would be too far off one way or the other. Things were very jumbled and chaotic at this period. Things just thrown in helter skelter with color combinations being the least of the worries of the army.
Take care, Sgirty