You can contact Eileen at Janome HQ, shes always been incredibly helpful when Ive rung her ... Even talked me through fixing my walking foot ... Result!
When I use decorative stitches, particularly when machine stitching the binding on my quilts with the blanket stitch, I always do a test run first on a scrap to check I have the correct S. length and Width ...
When Im happy I then stop sewing just after the needle has swung back from the binding lift the presser foot, pull the threads, cut them and restart on the actual item!
That way I have thread tails to bury at the start of the stitching and the locking stitch stays on the practice piece.