If you use Poly/Cotton for your top fabric, you need to watch how much Poly to Cotton you are using. Poly can melt with heat. You never know what someone will do with the items when your not looking. I have used double knit a lot for batting, KenmoreGal2 is correct in the fact that your runner will lay flat and wash like a dream. If you think this person will be placing HOT items, you do want to use something like Insulbrite or you can even use old ironing board covers (I always save my ironing board covers, you can cut out and bad spots and they are free). Good luck