All reasonable sounding solutions. In September in the Wind River Range where I hunt, it's pretty normal for it to be below freezing in the morning, up into the 60s or 70s in the afternoon, and back near freezing before I get back to camp. If I don't hunt in the cold, I don't hunt!
The best solution I've found so far is my regular three-finger shooting glove under a wool "fingerless mitten." (You know, the mittens with the flap that folds back, exposing the fingers) That works pretty well except that when it warms up, it is really hard to get the shooting glove out of the wool mitten...So, I'm thinking about trying to sew some home-made fingers into the mitten. I just got some good, thick cowhide (for mocsasins) that I think might work, if I can figure a way to sew it in without unraveling the knit.