I wish I could remember where I first came across it. I had just read Lee Cockerell's "Creating Magic", and I went into a sort of deep dive for leadership lessons from Disney. This coincided with a fit of nostalgia for 1980's EPCOT, which drove my wife a bit crazy. You can blame the Horizons Resurrected project for that. It was Disney practically 24/7 for a couple months there.

I don't know if the Yesterland blog post is the one you came across, but they do a good job cataloging the different retellings of the story and even include some of the artwork Herb put together that weekend. Definitely worth a read.

http://www.yesterland.com/ryman.html