I always leave a my batting extending past where I am going to attach the binding. If you make the binding 2" it will be perfect. Then just trim the batting to the width of the seam allowance. I think if you are hand stitching the binding that will be perfect. I think many do machine sew the binding and in that case you might need the extra 1/2" on the binding. I have used both widths successfully. Try it now, it will be great!