I hope I'm not too late to ask this on this topic... I, too, had difficulty staying actually IN the ditch on my first attempts. So, I chose a decorative stitch and used that pretty much OVER the ditch... just covered it up... It used a lot of thread, but I used a pretty thread and my quilty friends thought it looked nice. I added another quilt line diagonally/criss-crossed for more complete quilting using a straight stitch.
On another quilt (the one in my avatar) I used pretty thread over the ditch with a decorative stitch and then quilted inside the block using buttons. The pattern is a D9P.
I know there are no 10 Commandment-type rules for us, but is using a decorative stitch OVER the ditch frowned on by the quilt police?