I am glad to hear that your tank is doing OK from the spider damage. They are actually on my SPS, specifically my Acropora Humilis.
I was wondering the same thing. As far as dipping the corals, I don't think the spiders live on the SPS cause I only see them at night, specifically after midnight, on the corals. I think they hide in the LR. Also my SPS have encrusted onto my very large pieces of live rock so it would be hard to take them out. Dr. ROn said that he did not know for sure of any predators and that basically I am screwed. I am gonna send him some some of the sea spiders.
If this gets real bad I am gonna get ride of everything, my fish, rose anemones, and corals in my 120 and dedicate it to a Heteractis magnifica and a few clowns.