Now, lay the fabric out and measure where the pins are pushed in from each side. It looks like it's between 5/8" and 3/4". I will be using the 5/8" measurement so the piping isn't wider than the seam line. Now, I add the 1/2" seam allowances. The bias strip will be 1 5/8" wide to make the piping.
For each pillow, I'm going to need approximately 120" of piping. This will give me enough to go around the four sides and to finish the ends in such a way that you can't see where I started / ended the piping.
I finished the backs this morning. Here's couple of additional pictures:
I don't use any pins when stitching the zipper. I line it up with one of the lines on the zipper and then sew for a couple of inches. Then, I pull the zipper tab to close it all the way. I also lined up the edge of the fabric with the edge of the zipper foot.
Here's where I'm starting the lap on the zipper. I used my favorite notion - Wonder Tape - to hold the fabric while I stitched. This gave me the 1/4" overlap that I was looking for. Also, I used the extra zipper tape to make sure that I was missing the teeth and lined up with a measurement on the stitch plate.