So I rig a line from the mast to the topping lift about 2-3 feet above, at the mooring. That works. I don't seem to have a problem with the spreaders but others do. I'm seeing more of the plastic spike material banded to the tops of spreaders these days(a little late for you to fit some of that). Some boats are mounting the spike material on all mast surfaces, even the masthead.

I have a suspicion it has a lot to do with the bird population nearby. Conditions in the harbor must contribute as well. Inner harbors that are most calm may be more of a problem?

I have new sail covers on order. I picked Oyster as the color. I hope that doesn't change my bird dynamics.