I have two 3" X 12" dynaplates that are about 2' apart on either side of the center line of the hull. I will have to connect them to one another, and I use a stuffing box which drips a little (if I have tightened it correctly), so it might be a drop or two from time to time. But I like your idea of a thick piece of copper between the two dynaplates and using the .010 X 3 roll to connect everything, which will be in places that don't see salt water ever.