I just measured my own quilt (a Thermarest Regulus - synthetic fill), which is 70” long. It is 44” wide at the shoulder (fully stretched open; with elastic not stretched, it’s 40”), tapering down to 24” at the foot. I’ve found it to be sufficiently wide to tuck around me (6’ tall, 180 pounds, size 36 waist, size 44 jacket), with no gaps where cold can sneak in. I’m also a side sleeper.

Hope that helps.