Ok, here's a question that has been stalking me since I made the purchase: Do you think I'm likely to freeze my butt off if I use the Thermarest Ventra (40 degree) quilt in the high country. They say you should use a 25 degree bag (15 degree difference). I could bundle up, break out the chullo, gloves, and also break in the insulated jacket. I'm getting the impression this is something I shouldn't play with, given the unpredictability of the weather up there...