I’ve used it twice. Once on a 45” square quilt and the stretch was there but manageable. The next was more like 50” by 60” or so and the stretch was more of a problem. I quilted both on a long arm frame. I’m not sure how to mitigate the stretching but it seems like there should be a way. I want to try again someday because I love the quilts made with it. I did use batting.
it’s possible that putting the pieced top on the backing rail and the Minky on the top rail would make it easier to manage the product, but that might create new problems if the fabric bunched up under the presser foot.
I have bought Minky or similar product in 60” width.