It looks like the Verlinden colors are pretty close. The coveralls, called 'HBT' (for 'Herringbone Twill) are a light sage green when worn, a shade darker when new. The tanker jacket faded almost to a khaki when worn and the tanker helmet was close to forest green with tan to brown leather lining. The leather around the pressed fiber ear pieces was close to apple green (edged with brown liner color). Leggings were a light khaki / green (faded to khaki) and boots and other leather was russet.. NOT black! The British wore black boots. IF the crew as in winter wools, then the trousers would be the darker OD similar to an Ike jacket (you saw that a lot in the ETO during the winter), usually faded a bit lighter... if they had the wool 'field trouser'. OR they wore the lighter OD green wool trousers from the 'dress' or service uniform.
Don't forget tankers got greasy... and still do! (hence the German black uniform to hide grease) and that the coveralls, jackets and such were almost always messy.
These colors are referenced from actual uniforms in my collection... so they are accurate.
NO MORE BROWN 'LEATHER' TANKER HELMETS!!!!
Ron