There are some piano tuners I've found who are a bit on the spectrum, who believe they can tune a piano in a way that no digital device can replicate. I'm skeptical, and would like to see how this method holds up against one of these savants.

A tracking resonator bank should self-tune to any frequencies... so as long as the density of resonators is adequate, after convergence, it should paint a representative picture of the tone profile. Then you can try funny chords, or see how harmonics interfere, or see what happens when you hit 2 adjacent keys, etc.

Fun analysis experiments like this are why I made the free demo app (it runs on iPhone/iPad/Mac):

https://alexandrefrancois.org/Oscillators/

Check out the big brain on Brad....

Impressive. Thanks for the pointer.