I decided to go ahead and use the darker thread and stitched a straight line straight from top to bottom catching both sashing and cornerstones in the same color. It actually doesn't look all that bad ~ well, except for the wobbles in my line, lol. I have never actually stitched a sandwich so my lines are a bit wobbly every now and again. I will try to post a picture tomorrow of what I am working on. Thank you for your assistance.