xvimbi: Do you mean always play the white keys between the blacks? I would have thought when nescessary. Example: A well known piece, "Moonlight" first mov., bar 16-18. I've never dreamt of the possibility of playing that passage up between the blacks. Are you sure? The sister-passage bar 52-54 I play the right hand up between the blacks but my left hand I move down as soon as I can on the A-A octave third note bar 52. Is that wrong?By the way: This passage is a good example of advantages with big hands. It's relatively easy for me to grab 9 keys. When I compare my teachers hands with mine I can see that I can (potentially) grab 10 keys as easy as he can take 9.
If I move the hand up in the black area the thumb on the B will also press the C right next to it, so in order not to do that I've actually pulled my hand as far away as I could, thus playing the B out on the edge of the key.