Tonight I tried something similar to what TomS suggested with the S biner but used the tail end of my Atlas strap in place of the camo cord... MUCH BETTER!
I'm assuming I got things closer to "right" since I started watching TV and snored myself awake at 2:30am! Basement stays a constant 65, and my back was plenty warm.
Now I just need to find something convenient to carry to put under my knees to keep from flaring sciatic nerve
woke up with a numb foot, but that's not a suspension issue.