After reading about this, on the QB, I've also been using the Elmer's School Glue, for basting. I took the advice of laying out the batting first, then smoothing the fabric, on top of that. The batting doesn't shift, as fabric would. Also as suggested, I then fold back half of the fabric (at a time), drizzle the glue onto the batting (lots of thin lines/swirls), then fold the fabric back and pat it into place. If I use the iron, I hold it to the fabric, for a few seconds, then move on. I don't actually "press" it, just lightly hold the iron to the fabric. This seems to work better (for me, anyway) than pressing.
I've only tried this, with Warm & White batting. Has anyone tried it, with the higher loft poly batting?