The base color for German Armor was called "Dark Yellow". You can find photos of basic 'dark yellow" panzers as well as those with camo of browns and greens added to that 'dark yellow'. If AH ever adds earlier Panzers, you could go back to the Panzer Grey, but the Tiger and Panzer IV we have would be from the time frame where 'dark yellow' was the base color.
I suggest tracking down Panzer Colors, Panzer Colors II & Panzer Colors III, by Bruce Culver if you want to get some serious detail about German armor paint schemes.
Ok just for you Guppy.
Panzer Colors 1934-1945
1939 - OKH (Oberkommando des Heeres) orders RAL 7021 - Dark Grey factory applied all vehicles
March 1941 - OKH orders RAL 8000 (base color 75% coverage) / RAL7008 (camoflage markings) for N. African vehicles
March 1942 - OKH orders RAL 8020 (base color 75% coverage) and RAL 7021 to replace the previous colors in N. Africa
August 1942 - OKH orders RAL 7021 on Tigers at Eastern Front
December 1942 - OKH orders Tigers shipped to Tunis be painted RAL 7021 with thin coat of RAL 6003 overspray
February 1943 - OKH orders RAL 7028 as base color for all vehicles - camoflage patterns were RAL 6003/RAL 8017 or RAL 8002
October 1944 - OKH orders RAL 8012 as factory base color with RAL 7028 or RAL 8017 for markings
November 1944 - OKH orders RAL 6003 as base color with RAL 7028 and RAL 8017 for markings
After that shortages effected factory paints and RAL 7028 was factory base color with variations in colors for markings.
RAL 7028

Maybe it's my monitor but that really does not look like a dark yellow and I have not been able to find consistent WWII German RAL color charts, one even shows 3 variations of that color.