NICE job, Chester!
I follow in Jack's point; IF you are in fact trying to depict one of the 12 or so of these which made it into Stalingrad (and ended there) in 1942... they most likely arrived wearing dunkelgrau as a base-coat, with some having possible crew-applied sand, tan, or maybe a green, blotchy camo (and perhaps additionally a whitewash coat in the winter of '42).
The dunkelgelb RAL7028 color became Wehrmacht base-coat regulation in MAR 1943. The color was not likely available in the supply system for any units in Russia in 1942 - while there were likely some captured Russian tan or similar color available, and possibly also one or more of the colors being used for "tropical" schemes done on vehicles for North Africa (some of these tropic vehicles, along with some of the paints, apparently got sent to Russia later in 1942).
From this; while you probably should not use a D'gelb base-coat on a Stalingrad 1942 vehicle, using some sand / tan camo on dunkelgrau would be appropriate.
It looks great as it is - I'm just commenting to the historical accuracy aspect. The surviving 12 or so, which did not enter the Stalingrad pocket, went on to serve in 1943, and likely did receive repaint schemes based on RAL7028.
Bob