Do these colours look right to you ? Wehrmacht greatcoat

Could I just do them in white ?

Sure... In fact, I'd recommend it, since wearing  the overwhites/reversibles was pretty important comouflage measures during infantry ops in the Ardennes...  Troops that didn't have overwhites or the reversables (including Americans) grabbed whatever they could from the locals for white camouflage, pillow cases, bedsheets, tableclothes, whatever..

Where are my manners !

THANK YOU INDY !  (happy now ?)

Thanks to Al and Hans as well 

...........you're  welcome

Hans.  

As this is going to be a winter (snow) scene, could I wimp out of painting the ambush pattern on those smocks and helmet covers ?  Could I just do them in white ?

"Wehrmacht" is a bit too broad a description, Wirraway... It means "Armed Forces"... The Wehrmacht was made up of the Heer (Army), Waffen-SS, Luftwaffe, and Kreigsmarine remember... That said, it depends on whether you're doing Waffen-SS or Heer... The Waffen-SS would be the Mausgrau (Mouse Gray) of the SS uniform and Heer greatcoats are Feldgrau (Field Gray)...   The Mausgrau is on the gray side and lighter than Panzer Grey, while the Feldgrau has a definate greenish cast to it... I like Tamiya's shade of feldgrau for Heer Truppen as well as for Luftwaffe Field Divisions (Not paras though. That's another animal)..

Here are some pics of re-enactor greatcoats:

Take your pick. YMMV

That boxart looks a little faded out in your photo. The color you want is definatly a grey-green though. Here's a take on it by 'Ole Mac Mcconnell at the Mil Mod site.

Concensus is he got it all right. More pictures HERE if you like.

http://www.militarymodelling.com/forums/postings.asp?th=32990&p=1