Foam UQ gives cold shoulder to camper! Unfortunately, most 24 in. wide foam pads aren't going to keep your shouiders warm. Search HF for how to add "wings" to the upper shoulder area. On the cheap, some HD duct tape would suffice to join the wings to each side.
As a "canoe camper" I find that it's really simple to roll my pad around the inside of my pack. That gives everything more padding, including ME! It better protects my stuff, insulates it better and is so easy to store. I can use it to keep my pack sides up in camp or thrown under my backside to eliminate CBS. Win/Win!