If you are freezing in a 0-degree bag at 32-degrees, your bag may be wearing out or inefficient or your sleeping pad may be insufficient (getting cold from bottom). Also, any gap in the hood will let in cold air. I have a 2-oz detachable down park hood that I take when I anticipate cold conditions. That with a balaclava really solves the cold air from the top problem. I sleep really cold too, and have a 10-degree down bag and I have to have the hood totally tightened when temperatures get near freezing. My problem is getting the bag warmed up in the first place. Once the bag is warmed, it is really good to well below freezing. I take a short brisk hike before going to bed, hop inside with under-layer only so my body heat gets distributed into the bag and THEN put on my insulating layers if needed.

I personally would trust an Ursack in Emigrant, however, I would hang it high enough so rodents cannot get into it. Avoid camping in well-used campsites and pay attention to bear signs, and camp away from trails (about quarter mile). But I do agree that the bear can is quite handy and easier to use. And if taking the bear can makes you worry less and sleep better than the 2 pounds is worth it.