putty will probably be your best bet. The subject of winter gear for troops commercially available is better for the Germans since they had more access to it and it was more common to be issued.
Most US soldiers in the Bulge didn't have proper winter gear and it wasn't uncommon for troops to use white bedsheets as ponchos. You can sculpt in a scarf around the neck and some mitts or fingerless gloves and you won't be far off. Officers would be more likely to have the big wool coats.
My grandfather was a staff sgt in Pattons 3rd and he says they didn't have barely anything for proper winter clothing and it was a miserable time.
I know that is kind of vague, but those guys had it pretty rough over there.