What a fascinating chart. The tuning forks must be reliable. I'd be slightly scared of relying on an organ for pitch too exactly though; surely organs tend to be subject to a lot of rebuilding and alteration, and I don't know how easy it is to document the un-tampered nature of an early one? I'm not one bit sure how you estimate a pitch from a stringed keyboard instrument. I had no idea there was that much variation. It's also interesting that data derived from a single instrument can still differ quite a bit.
Mazie, ohje, I hadn't thought how complicated it is. I'm sure our predecessors would get the giggles at some of the things we do, or disapprove heartily of others. It's a completely amazing thought that we're just a handful of decades into a totally new era of music history: no one in the future need ever wonder how we interpret music, how we tune, or anything. they just have to listen to recordings.