When doing the machine stitching I think it would be easier and the back of the quilt would be nicer too.If using a piping than 2 1/2 would be good but with out piping can cut back for a tighter fit.I am liking the machine stitching vs hand stitching. I am trying to find the best method. I tried the stitch in the ditch...did not like that. I just did the zipper stitch, I like the looks of that.