Wow! That is really neat. I made poly quilts for all my children back in the day. They were backed with polyester and a thin flannel blanket was put in between. They were made out of 4 or 5 inch squares and tied in each corner. The kids still have those quilts and like Lori S said--they are so warm! I would take the advice of Lori S and quilt it very close to help control the sag you will get if you don't. Have fun and show a finished picture when you are through. You got quite a find!!