Forgot to mention: I'm about 5'10", and the 66" pad is effectively a full-length pad for me (my pack, crosswise in the tent, is a pillow base; my shoulders end at the top of the pad, and my head is on the pack/pillow. That means I've only got to have about 5' of me actually on a pad.

Just a quick thought; it might save you a few bucks and 3 or 4 ounces.