I am working on some grid quilting inside a quilt and here is what I do:
I pull the bobbin thread to the top and sew about 5 stitches at stitch length .4 mm.
Then I change the stitch length to 3 mm and finish the line.
JUST before the end of the line I change the stitch length back to .4 mm and do another 5 stitches. Trim threads - finished.
My machine has a memory function for stitches, so instead of changing the straight stitch all the time (that was a drag), I select the zigzag stitch for the start and end, set it to STITCH WIDTH = 0 and STITCH LENGTH = .4.
Now I only have to toggle between the zigzag and the straight stitch. I think I read that on this board somewhere.