As I suspected, the temperature at the top of the stairs is identical
to the temperature at floor level, currently 56F.

I was inspecting the damper and if I had a metal pipe or rod of some
kind, I could prop it up to keep the damper partially closed and see if
that makes a difference.

Also I was told that the glass doors increase effeciency. But when
they're shut, I don't feel much heat at all from the fireplace. It's
almost like it's all going up the chimney. When they're open, I feel
quite a bit of heat. I'm assuming that when they're shut, the wood will
burn slower but more effeciently, and when they're open, I'll get a
stronger burst of heat, but it will burn out faster. Does anyone know
how this is supposed to work?