Charles H wrote an answer about Mountain Hardwear Chillwave Down Parka - Men's on January 27, 2012
I'm about the same size as you are and I wear 35/36" sleeves in dress shirts. I ordered a large and the sleeves on the Chillwave were not long enough for me and I returned it for a MontBell Frost Line. Can't speak to your layering question since I never got outside with the parka due to the sleeve issue. Hope this helps!