I used to think I was pretty good a figuring out the roving myself until I got the 12:1 fiddle system... ugh.
Unfortunately Harken doesn't have a diagram of that <img src="http://www.catsailor.com/forums/images/graemlins/frown.gif" alt="" />

My advice is this: run it a lot of times until it seems right and has no overlaps (or maybe only 1). Trial and error