I saw it done as a demo at a show a few years ago, but if I remember correctly, she cut the back 1" larger on each side so after you sewed together, you would fold 1/2", then 1/2" again and sew to top of block on each side. You would end up with 1" sashing with seam down middle. She was selling a ruler to go with the technique, but don't remember who she was. I'm sure you could cut whatever width you wanted.
Last edited by yngldy; 05-28-2017 at 11:27 AM.