Tank German Dark yellow for my Plague marine

Hmm...

I think I would start with a mix of Olive Drab/Yellow for a base color and highlight with Dunklegelb. Maybe a touch of Desert Yellow on the most exposed areas for a chromatic effect.

But the OD would be where I would start to get that sickly green undertone to the scheme.

Finish that off with a Black/Green wash for the details to pop and you might have what you're looking for.

Im very interested to see how this turns out. :)

edit:

If it turns out too dark or not yellow enough you can spray on a a filter using water color paint. You'll have to seal it before touching it because water color paints rub off kind easy when applied this way, but you can change the tone easily with that method.

Experiment and have fun. That is my best advice. :)

Thx, yes i have seen a lot of people that say that buff is good for high light. But i think it can be good with weathering if want this darker

The Tamiya XF-60 is a good match for Dunkelgelb,I have used the AK Streaking grime with it.For German armor,I do lighten it with Buff,to compensate for weathering,but in your picture it looks dark.