Great article. I am not sure If I grasped every technical detail but I have the feeling you got it right, that there is no so-called natural tuning. There was a time before we could use modern measuring equipment, and people played and tuned their instruments differently, depending on tradition, location...Think about our voice.
Parenteze, mi remarkis, ke vi ankaux parolas Esperanton. Bonvenon en la eta Eo komunumo!
Exactly as you say, without measurement it's impossible tu tune exactly. Great example, the voice!
Dankon!