I like to level the sharps once the ivories (plastics?) are done. On concert grands, like this Yamaha CFIII, I find 12.5mm is best. Smaller or older models of grand can work best with the sharps set as low as 10mm, but this +12.5mm (elevation above the naturals) is good for:
1- an aftertouch that feels similar to the naturals (the determining factor)
2- clear release of the jack
4- a touch depth that leaves the sharps above the surrounding naturals (at aftertouch). That is, lower +elevation of the sharps usually leaves them touching or even burrying below the surrounding naturals – not good!
Of course, pianist’s individual preferences may dictate further changes: some (especially those with small hands/short fingers) prefer the sharps set lower than 12.5mm, so that they can more easilly move up & down the keyboard when playing far ‘into’ they keys.
AND OF COURSEST, once the key levelling & elevation is done (together with all other action regulations), regulating the depth of touch for each individual key must follow…