Captain, do you have a copy of the Clonmel Code? What other sources exist for the rules (over time) of duelling?
I have a small paperback book I picked up at a used bookstore called Gentlemen, Swords & Pistols: Fantastic True Tales of Duelling in the Old South, by Harnett T. Kane (NY: Ballantine, 1974, SBN 345-23756-0-125, (c) 1951). I haven't gotten around to reading it yet.