I had to do corner darts . I made my own cording recovering the old cording from the old cushions. Save as much as you can from the original. I used a zipper foot to apply the cording. get it as close as you can keep reading on to older posts it goes on and on!
This project took about a month. Every cushion got a new muslin cover.
This couch is probably 10 years old. It is looking awesome.