Agree with lots of the comments. For sitting on a high ridge glassing in the rockies in November, a parka is the way to be thinking. I also think the fill weight is more important than the fill power. 5 oz of down just won't cut it for what you want. You probably need 7 or more ounces of fill weight, preferably 800 fill power or higher. The RAB suggestion is a good one. Their Electron has 7+ ounces of treated 800 fill down (maybe 850). Their Neutrino has 8 or more ounces of 800+ fill power down. For the same use you're talking about, I went with a Montbell Alpine Down jacket with 7 oz. of 800 fill non-treated down. At 300 bucks, you get 2 ounces more down than most the hunting brands with a 3 ounce weight penalty. I'll gladly carry 3 extra ounces for the added warmth for 100 bucks less.