Does anyone use these for a knee pillow? http://www.jacksrbetter.com/Pillow.htm

I tried out my new WBBB 1.1dbl this week and had a great night's sleep. I noticed quite early that I had knee hyperextension issues. I did not have any of the calf ridge pressure I have read about. The ridgeline was pretty loose (bends to a 90 degree turn per Brandon's setup video). I thought I had a pretty flat lie with the feet hung higher than the head. I knew some support would help. It was an easy fix. I went in the house and stuffed a sack full of clothes for a knee pillow. The question becomes what do you do on the trail when you don't really have enough extra clothes? In the colder months it might not be a problem, but in the summer I don't have enough extras to fill even a small stuff sacks. Are these Graham pillows durable? Big enough to prop up knees? Reuseable? I appreciate any input. Thanks.