i also have used minkee many times for quilt backs- with my long-arm--my granddaughters call them the (get-naked blankies)
it does take a little (practice/experience) using fabrics different from the cottons you are used to...especially poly knits...that stretch. with the minkee it is important to smooth it but not stretch it- and if a batt is used one that allows the most distance between quilting (or flannel) is a good choice- the less quilting done on the quilt the less chance of stretching anything out of shape- but i have quilted fairly heavily without problems-
just remember- smoothed not stretched. and one direction stretches more than the other direction- sometimes (if possible) if you can load it with the stretch going (across) instead of the length- you are less apt to stretch when rolling the fabric on the bars