The packaging on Quilter's Dream batting said it shrank only 1%.
I had a Michael Miller fabric shrink over two inches in width. Assuming 44 inches in original width, that's over 4% shrinkage.
If this was a quilt 100 inches long - the batting would shrink 1 inch and the fabric would shrink over 4 inches.
Whatever works for you.
By the way, some sources say there is a tiny bit of formaldehyde in Retayne.