If this gets implemented I would like to see 442 as the upper range. My flute, for example, can be tuned that high to match whatever you throw at it. Some orchestras tune to A=442. Some percussion instruments are made at 442. Even the organ at the church where I play is at 441 (I don't know why). The point is, 440 is not the highest pitch encountered.
Yes our piano tuner has my wife's piano tuned to 432 Hz because of its age. it is over 100 years old.
He also tunes the Rochester Philharmonic Orchestra's piano which he says is tuned to 442 Hz.
Thus a few Hz on either side of 440 Hz is the ideal change if such change can be made.