I have a 30 degree bag and am looking for a colder weather bag. The 30 will take me comfortably down to 40 degrees, bearable in 35 if I pile on some nightclothes. For colder weather I don't see myself going below 10 degrees. I am been looking at a WM Sequoia MF with ovestuff from Hermit's Hut. Should give it a -2 rating or so. Will that be too hot at 30 degrees? I feel like I could vent it a bit if necessary, but have never actually slept with a good low temp bag in cold weather.