I find this thread very interesting...our last NB suffered from minor galvanic corrosion at 3 years old despite only rarely ever being hooked up to mains, having anodes, galvanic isolator & being blacked annually, however, it was kept in a marina & I was advised the corrosion had probably been caused by either being moored near a poorly earthed boat or steel pontoon stanchion.
We are considering a new build on a Colecraft or Tyler Wilson shell & as & when we take the plunge I intend to go for maximum protection against such corrosion, however, as with all things on the cut everyone has a different view as to the best protection!