I have done this several times and love the look and feel of the finished quilt. I have worked out my best way to stay on track is to mark the very top and bottom with hash marks every inch. Then I just do easy wavy lines and use the hash marks to stay on track. I start in the center and move the right going top to bottom and then turn it around and do the other side all in the same direction. Since there is no line crossing, it is not a problem.
It does take a lot of thread, but I love the results. Here is a medium close up of one I made from a free Craftsy class.