I was considering the Montbell pants but didn't get them because of the quilted construction. I have a WM Meltdown and a MH Sub0 and they are warm because of the baffled construction. I just cinch the waist and cuffs as taught as needed and I'm warm. The Sub0 is a size larger than I normally wear but when the air isn't allowed in it's great. The Meltdown fits like a glove so it needs little cinching to keep the air out. Like Jim said, wear a layer under it and you'll be good.
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...ask for the old paths, where is the good way, and walk therein... (Jeremiah)