I abandoned the polyester batting because I couldn't get the basting spray to work with it. Then, someone on the board gave us the link to Sharon Schaumberg's (sp???) "Basting With Boards" videos on You Tube and I've never looked back! I don't make many large quilts but this method has made the sandwiching process SO much easier and I can now use any kind of batting with the assurance that the back will NOT pucker. I only use the spray now on very small pieces. The "Boards" is a great technique and certainly worth a try. Just "google" "Basting with Boards" and scroll to the video showing the two bright pink pieces of fabric in the thumbnail.