Tonight I started putting the frame of Zs around the rice stitch border on my needleroll. I notices that no matter how I try the tension on my backstitching when I am going diagonal is looser than when I stitch on a straight line. Hmmm..... it sort of sags and I'm afraid to pull it too tightly because I don't want to make the holes larger in the fabric. Does this happen to you? It's not really noticeable overall but I can certainly see a difference when I look at the stitching.