I found traditional machine SID too nerve-wracking. I use a serpentine stitch now. This makes a wavy line so that I only have to stay approximately in the seam line when I am using it. Small deviations do not show. I just use a regular metal zigzag foot for this (not an open-toe embroidery foot, as that allows too much fabric to gather near the needle). The end look is different, but I like it.
Here is a link to some samples of serpentine stitch. The one I am using on my Bernina is closest to #19 in the photo. I adjusted the stitch width and length to make mine a little tighter wave: