Sizing: I am 5’10 165# 40” chest, 32 waist. I was recommended a medium. It is a perfect fit. Works with a button down or henley. Very similar to my size 40 613. Only noticeable difference are the forearms are definitely wider on the 656.
Leather: The Horween is superb. Sweatshirt soft right out of the box. It makes it very comfortable to wear from day 1. It feels a little lighter than a 118 or 113. Closer to a 626 but that may be due to the pliability.Not sure if it is.
Color: Goes from dark chocolate to a reddish tint depending on the lighting.
Collar: Described as real mouton. Probably is. It is of decent but not amazing quality. Perhaps a bit thin. That may be historically accurate.
Overall very satisfied with the jacket and strongly recommend.