Hi,

I had a #3 - yes, with the full zip, one could use it as a quilt-type cover. I would not worry about sleeping too warm. Although I liked the comfort of it (stretch baffles), some of it's baffles were lacking in down. I believe the temp ratings are pretty accurate assuming one is zipped up as the stretch baffles move with your body and trap in a lot of heat. However, I also believe that if the stretch baffles were not present, the bags would not be as efficient because of the lack of down fill weight. So...the bag(s) may be considerably cooler if used as a quilt but ideal for summer use. I hope that makes sense.