I love the Coldgear. With colder temps I wear a pair of fleece wading pants over the UA then my insulated pants. When it gets extreme I then add my insulated bibs over that. On top I start with UA short sleeve shirt, coldgear mock, two fleece tops, and then my parka. This set up seems to work for me but I can say that I have never hunted in the temps you are talking about. Coldest for me has been day time temps around 20 degrees with lows around 0 degrees.