The center now measures 64 1/2 inches - I have a bunch of 6 1/2 inch (unfinished ) squares that I want to use as the last border. I need to add a narrow border all the way around the 64 1/2 " center to make this work. If I add 2 1/2 inch border all the way around wouldn't I then have 67 1/2 inch center? Oh, you can see why I am having so much trouble - I just can't figure this out today.