i think hand and finger differences can be huge obstacles at first. for a long time i couldn't understand why chopin and rachmaninov were just man-handed pieces. i would attempt some of them with ill ease. then, either in a book or on the internet - see the actual SIZE of these composers hands. of course they composed for themselves (their individual reaches) and for their particular techniques at the piano. chopins fingers being very thin and long - and rach's just plain huge (like his feet).
For me the most interesting thing about Rachmaninoff's writing is not the thick chords or big stretches, but the fast passages in notes that are incredibly close together. My theory is that his hands were so huge, he had to train them specially to have them play in smaller spaces. Look at the prelude in c minor, for instance, from op.23, or the prelude in e-flat minor, or several passages from the Corelli Variations, the b minor etude, I could go on and on.
Rosen wrote about how his teacher Edwin Fischer had ideas about how the kind of hands a composer has determines their music. So Brahms, with his thick, stubby Teutonic fingers, wrote also thick-textured music. Chopin, with his spindly digits, wrote light, lyrical and long lines. Rosen disagrees because there are so many examples which contradict the thesis.

Walter Ramsey