After sandwiching and quilting, the backing of my quilt extends a little more than 3 inches past the edges of the quilt top. Do I fold this fabric over the front and use it for my binding or do I need to cut the excess fabric off even with the top edge and sew on a seperate strip for my binding? If so, how wide do I need to cut my strips? This will be my first time to do a binding and I want it to be done correctly and look as nicely as possible. Thank you in advance for your help.