In search of the perfect keyboard for my arthritic hands I noticed that keys that were easy to press irritate my fingers less. Makes sense, but some other factors were also involved. I also noticed that digital keyboards tend to hurt my knuckles even if they were easy to press. Other observations that seemed to contribute to pain was smooth key surfaces that your fingers slip on after a few minutes of play. Ivoryesque keys seemed to feel better, but if other key surfaces were kept very clean, these differences were minimized. Then there is another factor: weighted keys hurt more that synth action keys. In any case, I made a table of key weights I tested using Nickels and Dimes and a kitchen scale. I subtracted the upweight from the downweight to approximate the friction. It is interesting that to me, the lower friction keys seem to feel nicer than their weights would suggest. Many techs seem to think that heavier weight keys are better with lower upweight, but apparently Bechstein didn't get the memo and their keys feel amazing and play like a dream. It helps that the sound of their pianos is out of this world. I want to start a GoFundMe...
I'll update this in a clearer format as soon as possible.