What I have starts with a diagram and short blurb by Hal from an old web site, and a post to RSB dated Friday, September 12, 1997. I don't know if he lurks over here or not, but he does over at RSB. Once in awhile, he'll send an email to a regular and ask that it be posted, but because of all the bickering that has taken place, he rarely posts over there anymore. In fact, now that I look again, this might even have been an email exchange with Ron Hudson.
After spending a couple evenings with Hal, I started saving the discussions, intending to try to expand on his work in writing, and ended up with 54 pages, including diagrams! When I posted that I had it on RSB a few months ago, I ended up sending over 50 copies of it out, so there are probably a few over here that have it. I'm not sure we'll ever get closer than this to having it in writing.
I really wish Hal would write down some of his stories from over the years. After all, they go back to the days of Greenleaf!