@steve - thanks for the info and the picture. I was planning on this jacket as an insulating layer for camp/very early morning hiking. I would wear it to bed in early summer, but my quilt is good to ~40F with just a T-shirt, so I won't need to wear it often.
@tim - thanks for the suggestion that the half sleeve is more like a vest. I currently carry an old patagonia powerpuff pullover, but it is wearing out, hence my reason for trying to make a new coat. I wear my windshirt all the time while hiking and around camp, so I am thinking that a vest with extra armpit warmth might work well for me.