I know a little bit about poncho liners
I lived in one for 13 months. They are better than nothing in cool weather but way too light on loft and way too heavy on ounces. A new one weighs almost two pounds. For hot weather they actually make you feel cooler the way they wick away moisture. I lost one to shrapnel, but I was so proud of it I had a hard time replacing it with a better one. You can see through a poncho liner. If you are wearing a poncho for days on end, the liner is a bit of a relief at times in hot weather and a real blessing in cold weather. It got down to nearly 35 degrees many times in the mountains. I think I would keep looking for something better though, IMHO. Mule
There are only two kinds of people that understand Marines: Marines and the enemy. Everyone else has a second-hand opinion.
Gen. William Thornson, U.S. Army