Keep in mind that the cadenza from The Nutcracker is not played as it looks
on the page. The 16th note figures are not played with the left and right hands
simultaneously, as it looks on the page, but instead you play them twice as
fast, with the right, then the left, alternating. This is how everyone does it,
though some play both the figure descending, while other play the right
descending and the left ascending. You have to adapt a way to get to the final
rising arpeggio near the end, while staying in the rhythm. This is often done
as a glissando, finishing with a sixth chord, with F flat and D flat set, then you
put the F and D back in natural in the next chord.
Alway play from the original music, so as not to confuse the dancers.