In addition to Kimono silk you can also use their 100 wt poly microquilter or Wonderfil's product Invisifil. Not near as expensive as the silk. These threads really do sink right down in and as long as you are right in the ditch of your applique it will not be noticible. I use these products for ditching and hand applique. While hand applique is much easier to make the stitches truly invisible these products will come super close to invisible with machine turned edge applique.