I agree with Medicine Man!
For me at least the UQ is 75% of what keeps ME warm. I've slept down to (about) 50 with a No Sniv as an UQ but only a fleece blanket on top, no problems. Reverse the two & It's "shiver city" all night long.
When you have a backpack on, no matter where you are, you’re home.
PAIN is INEVITABLE. MISERY is OPTIONAL.