When you use poly batting, my suggestion is to spray your quilt fabric and not the batting....it seems to do something to the batting when you spray it directly on it. or maybe it was just the brand of poly batt that I used at the time.
Otherwise it works just as well as on cotton batting.
I've had a couple of quilts that I basted a couple of years ago and never got around to quilting until this year and it still held well except for around the edges and I gave it a light spritz again. I do NOT spray heavily.
warm quilt hugs, sue