I'm running the demo on the 4920 right now. Still have about 4hrs left. Realy like it. I have watched and checked by spraying right up against a pivot track all the way around. Then when going back and forth it's easy to see if it goes on/off at the right time. From what I can see it does a good job. I just need to tighten up my boundry lines a little. I made some fields a little bigger then what they are.

I haven't played with the timing part of it. It seems to work pretty good like it is set.