I got behind reading this thread for a week or so, so I'm catching up. A couple comments about earlier questions:
Judging the temp by using the temp in a nearby town can be very misleading. Towns often are built along rivers or creeks. At night, cold air settles in river bottoms and often those are the coldest places around. Camping even 100 yds away from a creek on higher ground can make a considerable difference in temps. On the large scale, higher elevations certainly are colder but in what you might call a micro-climate, that's often just the reverse. When snow is melting, it will often hang on much longer in the bottoms because the nights are colder there. Think thermals.
As for a bucket of burning coals in a tent - count me out, thank you. Indian tipis had open fires but they also had very large vents in the top controlled by long poles to move the flaps as needed. They could be opened up a lot more than any modern tent, making the whole tipi into a big chimney. If you read historical accounts about tipis, they were also usually very smoky inside, especially during storms when the barometer was falling.
Since I use llamas, I'm not as concerned about bag wt as most of you are. 5 lb for me is no big deal. My bag is close to 40 years old. It's down and in excellent shape but back then, they used stiffer nylon. It doesn't nestle in nearly as well as newer bags made of extra soft nylon so it leave air spaces, especially around my shoulders. I really need to replace it for late season hunting so I've been following this topic. I need a bag that's actually good for 10F, not just rated for 10F.
