I got a tall, and it still seems if I have a heavier sweat shirt on underneath that it's pulling still. So maybe at 5'11 one needs a TallTall (?). But the size fits other than the apparent  lack of space between the waste and shoulders. I'm in the healthy range at 5'11 and 170lbs, normal length arms. The length of the pant legs is perfect and it's fine without a bulky sweat shirt underneath.