Any time I do it I use a low loft batt and sew through all three layers at once. Then I trim the seam allowance to about 3/8". After I turn it right side out (birth it) I top stitch about 1/4" from the edge all around the outside to finish it off. It leaves the edge no more bulky than if you used a regular double fold binding. I've never tried it with a high loft batt though. I do this for some of the quilts I donate because it's quicker than a traditional binding. Hope this helps.