Back in the day ( the 70's) all of the quilts I did were the pillow case type method . This was of course before all of the great gadjets and gizmos we have now. The biggest chanlenge was to get it to be flat and true. The layers all have to be exact to have to come out flat in the end. There was always ...always some puckering because all of the layers did not play well the turning process. The larger the quilt the worse it got. I would not recommend this for full size quilts or larger( if you are a beginner or have not done this method before) . There are so many other methods that will give better final results. If you do want to do the "pillow case" type method . I would recomend that you do a Tack stitch type method. This is similiar to tieing. You take several "in place" stiches at places that you may have tied. Take a large zig zag , put the stitch length to zero and take several back and forth stitches. This will secure the quilt like tieing. You can do some simple quilting once this is done , it will give you a good idea of how much you can quilt comfortably in each area , keeping in mind the chance of puckering. Do refer to the batting packaging for how far apart the tacking and/or quilting can be placed. Each batting has differnent recomendations for quilting distance.
I still do the tack method , and place them pretty close together ( 3 to 4 inch ) for some kids quilts and especially if the batting is thicker.