I normally wear monkey arms in the button downs, but normal sleeves in the thermals/henleys. Mauro said these sleeves will be longer, so I am going to go with a regular sleeve length and my normal size. Hope it works out.
If anyone is interested, I'll probably be selling my polka dot flannel from last year. I've only worn it once. I've bulked up a little and some things aren't fitting as comfortably as I'd like. You can message me if you'd like.