I'm a hot sleeper so I typically buy my bags a bit cooler than I expect to be out in. Having something over the bag (any shelter or even the AMK bivy) will increase the effectiveness of the bag too. The bag is new and hasn't been tested in the cold yet but by my standards it's fairly heavy (physically too...It weighs 3 lbs). I too have been trying to find out if the -7 is a comfort rating or not...seems like a comfort rating but I haven't been able to confirm. It's all subjective anyhow...no two companies use the same tests.

Reviews like this one suggest that it's much warmer than advertised...though I've read reviews that indicate the opposite too. One thing that is consistent in the reviews is that it's a top quality bag.

As for the fuel cans I'm going to experiment with using chemical hand warmers under the concave base of the can and keeping the can in my sleeping bag at night.