I'm not sure that this is the answer you are looking for, but, from my experience as an old amateur pianist, playing the piano is not so much about dexterity. It is MUCH more about listening and understanding music. The instrument that you have to really learn is your brain. You have to be able to listen to each note in the scale, and to listen to as much notes as you can (even the most deep notes within the chords). You have to sing the notes as you play them, and to find the poliphony that is everywhere in good music. As you do this you become a better pianist. If you dont' do this, no amount of dexterity will make you a good pianist.