I use 2.75" binding with a 3/8" seam allowance, adjusted slightly depending on thickness. Instead of doing a sample to test, I set the stitch length to a little longer and start my sewing of the binding a smidge inside 3/8" and sew for about 8-10". Then I reach back and test the turn of the binding, which is my opinion should be completely filled with quilt and turn to the point of the stitch line on the back. I set the stitch length to normal and make the adjustment in the seam allowance. Rarely do I have to remove the stitches because the seam is too wide, but if I do they are bigger and easy to remove. If the first stitching was too narrow, then when I get back around to that side, I just sew past the original start point for 8-10" until I overlap where the right width is.