For go to ground situations in non-winter temps I use ¾ length old Therm-a-Rest Guide. Also, I found it "okay" during the summer if it was in a DL GE hammock or between the hammock and UQP on a SL hammock. I looked at the current fancy (over $100) air mattress types at REI. It seemed to me that I could just buy one of those $1.00 "swim" air mattresses mentioned early and then put some cornflakes in a ziplock bag and crunch them next to my ear every half hour instead.

I understand the advantage of Yellow/Silver is there are no moving parts - nothing to blowup/seal. Others have said there is no radiation reflection benefit from the silver side because all contact is conduction. Just me, but my experience is comfort is worth a few ounces. We had no "ultralite" materials when I did my Thru-hike. Yet we made it. We didn't suffer (much). But we weren't trying for any daily/speed records. Just get up, have breakfast, break camp, hike until nearly dark or planned camp site. Repeat.