We are approximately the same size and I have room in the 46, but I don't think I would have been able to size down two on this piece. I think the 42 is 43.5" chest, 28.3" length, 18" shoulder, and 26" sleeve.
Up! I took the largest size (46). I'm 6'2" 185lbs and typically look for 19" shoulders and 44" chest unless I'm intending to do heavy layers underneath. That rarely puts me in a size 46, but I like how it works here.