It is one thing to use the 12th tuning but there are many other things that must be considered. I explain and demonstrate live with a screen video recording on my Fazioli F308 and the PianoScope program.
My video demo that shows how we should use more tuning bias on the initial attack rather than the decay value.
The human musical ear is much more attuned to the initial attack rather than the steady state settled response. It is a known psycho-acoustical effect that musicians understand intuitively.
We also have frequency modulation going on in the piano, and as an electrical engineer I can understand that and even explain it more technically.
The coupling mechanism of all 3 unison strings together also reduces the FM effect and flattens the result by about 1/4 cent. This all needs to be considered.
In this demo I explicitly talk about all these effects and demonstrate how at the end a very solid stable beatless attack of a 12th, which is an exact frequency ratio of 3:1, makes the sound extremely coherent.
The FM effect is different when all 3 strings are coupled and I demonstrate this also.