Many thanks for your diligence in chasing that information down!
I was aware of the Campbell reference, but couldn't put my finger on it. I assumed Campbell got it from Hatcher's Notebook. So, I went through Hatcher's Notebook with a fine-toothed comb, but couldn't find it. I thought perhaps that I had overlooked it. So, I posted here hoping that someone else might have seen it.
I also appreciate you searching Brophy and Canfield. The Canfield account is close, but not entirely accurate.
I have the Springfield Armory test report recommending the hole. And Hatcher's name is nowhere in it.
Thanks again for you diligence!
J.B.