I also am not fond of "pillowcaseing" a quilt. just too chancy to have a mess. but, if you do, you definitely need an even-feed foot. lots of pins ! thin batting. after I sew the edges & turn the quilt, sew opening shut, --I like to stitch-in-the-ditch about 3/4" away all the way around. even-feed foot necessary ! also need to in again. it then looks like there is a binding all around.
this method makes the quilting harder too because you can get puckers at the end with too much fabric---and you have nowhere to go with it.
Definitely do not cut off any fabric. if you squared the quilt when you started, that fabric belongs somewhere !
But best of all---use this method only for smaller quilts. it wastes more time than it saves.
In my humble opinion.