I am the exact height & weight as you, 5'9" 180 & I wear mediums in everything. No, they do not suffocate me, I don't know about triumvir flannels though but tee's, jackets, sweaters, etc I wear M.
Only thing that bothers me is that tee's are a bit too short :[ but Larges are too damn big & take 3-4 washes/dries to get the perfect fit.
im 5'8.5, 155-160lbs. slight gut. waist about 33/34. I could of sagged a little bit. I suggest the large if the 15lb difference is in the gut. I'm wearing a M in this photo
~Lefty
If I wear large in the flannel and tee shirts should I get the hooded zip parka in Large as well? I'm only wondering because I have a W+H hoody that is XL, and this CYC talk...