And even IF the weight needed to depress a key IS 50g
No idea how reliable this is.. but if it is, then clearly this stuff matters to top performers, so in theory should matter to anyone who wants to be a top performer?
"Horowitz often told his technician that the keys should go down if
> he simply blew on them. To achieve this,{Franz} Mohr found it
> necessary to file down the sizes of the hammers. Horowitz required a
> precisely 44 grams of key resistance, but full-size hammers were too
> heavy for an action of this gram-weight: the average Steinway is
> weighted to approximately 50-55 grams...."
I also found another site that stated steinwey's current standard is 52g, tapered to 47g in the treble.
...Though at this point i think its debatable that such specifics really have much to do with the OP question.
__________
EDIT:
Although - perhaps one might draw a conclusion that horiwitz's advice wouldve been, dont wast time strengthening your fingers (or shall we say "the muscles that control the fingers movement"), play on a lighter piano.
^not that I see any reason to think that we should all mindlessly copy him without further thought though.