Dave, a couple guys around here run that foward arm. They have a shock cord running from about where the diamonds attach on the mast out to the furler. This preventer for the jib sheet seems to work. If you haven't you might want to try it first.

I was just rereading your orig. post. Remember you set your rotator by sheeting in your sail while going to weather and looking at the lee side of the sail-mast junction adjust the rotator so the air flows smoothly into the sail. Depending on the sail you might find the spot to rotate to a little more or less then the shroud.

Have Fun,
Mike