Hi Nick
I think you're on the right track with copper rivets. If I understand correctly, what's dexcribed as copper nailing is, in full size, actually copper rivetting (hole drilled first, then rivet pushed through hole, rather than nail hammered through wood) with the end of the "nail" coming through inside the planks and clenched over a copper washer or rove. This is the way my Wideawake hull is fastened. I maust add that I didn't build it! If you're interested, I think there's a sketch diagram in the original article showing how it's done and i have some pics of the hull which also show the finished look.
Cheers
Guy