I think you just described my situation as well. What percentage Lugols to water for the dip? I think I am fighting a losing war this bacteria. Thanks for chiming in SPS store.
Most Lugol's do not have instructions for dipping but I think Kent Lugol's might. I would suggest picking up the Tropic Marin product and I typically use 2-3x their dosage recommendation without trouble. I also vigorously shake the corals in the solution to ensure that the slime/crud is sloughed off the coral.
I actually found Kent's instruction on their website for Lugol's. Since most Lugol's are the same concentration this should work for most products.
"Directions for use as a Coral Dip: In a separate bucket add 40 drops Lugol’s Solution to 1 gallon aquarium water, and immerse coral for 10-15 minutes."
Obviously you shouldn't typically need 1 gallon of dip but I would suggest about 5 drops per cup (double dose). And remember never to add Lugol's directly to your tank. Although many people use it to dose iodine to their tanks and can become toxic if not done carefully.
Also, if you're carbon dosing make sure to stop that as soon as possible. We actually ended up bleaching all of our tanks and live rock to completely eradicate this disease and then recycled everything. This was very extreme but the results were perfect, our tank look better than ever. I personally would not recommend this action for any aquarist, I'm just sharing our experience.