His results are interesting. I have no doubts about his conclusions. It's just that his conclusions should not be extrapolated to any other Holga than the one the tested.
My results only pertain to my Holga and none other.
A scotch tape and loupe test, using the text on the end of a lit light bulb as a focusing target and a tape measure took me all of five minutes. If someone wants to know the focusing characteristics of their Holga, I'd recommend running one's own test.
I've yet to verify my results with a roll of film so I'd say the jury is still out on my method.