As far as I can tell it's always been easy but unpublished. Therein lies the hard part.

On the other hand, remember that I'm presenting this in a sort of "this is where I'm at but it isn't fully tested" state. If 100 people now post well documented cymbals demonstrating these differences don't work that would also be a step forward. But not helpful in the short term. Only in the long term science way of looking at things.

I don't have more data because I already spent something like $500 just getting well provenienced examples of these cymbal eras into my hands. I have to pay exorbitant shipping fees to get them here. It's part of the price of living on the other side of the globe.