IH-2526J Iron Heart canvas jacket

I bought this jacket over the summer (absolute steal on eBay), BUT the issue is that the jacket is snug. I can only wear a t-shirt underneath. Also, the cuff is too tight for me to wear a wrist watch, so I leave the cuff unbuttoned. I wasn't sure if this is considered faux pas for a jacket this nice. Did a quick Google Images search, and turn out that most people do leave the cuff button undone. Vindicated!