Another option to try is SND, which is Stitch NEAR the Ditch -- or Stitch NEXT to the Ditch. I do this frequently, because it is done on the "high" side of the ditch, and makes everything lay nice and flat. I'm doing it on a longarm these days, but when I did it on my regular machine, I used an edge foot because it would help me to travel right along the edges. Maybe you could check your box and see if you have one of those feet for your machine...