I don't do a lot with Minky or fleece myself but I have done some, especially a number of years ago when I was using a friend's long arm. We always had to manually adjust the foot height -- I think the manual suggestion was to use a dime as the default but we had to move it up quite a bit from that.
I also find quite a bit of variation on the grain/stretch of the fabric and that something it is just easier to try turning the quilt around and quilting from a different direction and suddenly things just go better.
Good luck and I'll be watching the responses too.