Mike;
Hi! Great-looking start / WIP on that -222!
20 PD insignia... Russia, "winter 1942"? Hmmmm. I think you may need to be a little more precise! IF it's to be "winter '41 - '42"... You can I think safely go with either yellow or white and either painted onto the straight dunkelgrau of the period. Many vehicles in 1941 still sported their insignia in the yellow often seen on the Poland and French campaign schemes. As Barbarossa rolled on and stuff got repainted, insignia became more commonly white.
As your 222 is going to be in winter, you do have the option of a whitewash overcoat of varying completeness in later 1941 - in which case, those markings would be left exposed on small dunkelgrau patches.
IF instead you are speaking of say DEC '42, so "winter '42 - '43", you should probably stick with white insignia. You would have some option of later '42 field-mods to the paint-scheme. Many vehicles had received field variations of gelb or of rotbraun or a green added over the regulation dunkelgrau still in effect at the time. While these were non-reg colors and applied in none-reg local patterns, there was a fair amount of non-gra camo going on Russia theatre vehicles in later 1942. The PD insignia may then either have remained in small dunkelgrau patches, or have been repainted on the prevailing coat. And of course, you still have whatever winter-wash job you are thinking of!
Hope this helps you some!
So what do you think of the Tristar kit? HobbyBoss, Bronco and Tristar all make "modern" kits of various of the -221 / 222 / 223 cars to follow up on those old but fun Tamiya versions out since 1970 or so. I have several of the HB and Bronco kits, and have built the HB 223 kit (really cool, super nice kit but full of significant errors!), but have never actually touched or seen the Tristar offering.
I'm looking forward to seeing whatever transpires from your fine start!
Bob