I have a question for Western Mountaineering Ultralite bag owners. It's time to upgrade my old synthetic bag and I like the looks of the Ultralite. I would like to use this bag for late spring, summer, and early fall. My question is: Is this too much bag for summer use? Can you vent it enough to get by when it's 40 to 50 degrees? I'm 6' and 185 lbs, how is the fit? I have a good winter bag so this will be mostly a three season bag. I will also probably use it for an overbag for my 7 year old son in the winter time, with his NF Tigger inside this bag, we have done this with my old synthetic and it works well. Any help or comments would be greatly appreciated.