This is another fascinating read and really sheds some light on the Graves story. I had no idea that he was so driven by the Observatory trial results, and, as you concluded, this adds to his credibility as a collector. It was not just about having the most expensive or most complicated watch but it was also about having the most precise one.
Well, this also serves as a good tutorial on the Observatory trials. How lucky are you to have a chronometer that competed alongside the Graves piece.
Thanks for investing the time to write this history mystery for us.
Best regards,
respo