I found this on the lightnetwork.com website:

"I am programming 2 DL1s with a Hog3. I have a 4-layer v3.2Catalyst, feeding 2 layers to each DL1. I am trying to sync the layers going to each DL1, so the media is running to each at the same speed, and at the same start point.
I have already tried sending the start point, but it doesn't seem to help.
While I'm asking, does anyone know the optimum resolution I should set in Cat for the DL1s? I currently have them at 12xx X 768 60HZ".