I did finally actually use my airbrush today, just to add some dunkelgelb to the eldest of my Elefant models, and bring it a bit more into line with the two more recent builds. Above is the result. And below is an older 'before' pic. In the picture below, taken before I'd painted the two more recent Elefant, you can see I'd done some rather clumsy dark wash weathering on the old Fujimi model. I hope the above pic, with the Fujimi Elefant at left, shows that I've softened the look a it a bit?
So, I've done a bit of research, and this is what I've come up with, for now, using the Vallejo ranges of acrylic colours.
Rotbraun RAL 8017 (red-brown) - Vallejo Model Air 71.041
Olivgrün RAL 6003 (olive green) - Vallejo Model Air 71.092
As yet I'm undecided re their standard acrylic series:
Dunkelgelb RAL 7028 (dark yellow) - Vallejo Model Color 70.978
Rotbraun RAL 8017 (red-brown) - Vallejo Model Color 71.041*
Olivgrün RAL 6003 (olive green) - Vallejo Model Color 71.092 (poss 70.894?)