I haven’t been in practice at the piano since 2006 or somewhere there, but three or four years ago I felt like taking on something difficult as a summer project and so set out to learn this movement and a Chopin/Godowsky Etude. By August I could play the movement pretty well, except for the passage at 0:48-0:50 here. I practiced it literally maybe an hour a day for three months, but I just couldn’t get it spinning. How Hamelin and Libetta pull it off at this tempo is beyond me, and Lib’s Naples 1995 recording is one of the most hair rising stunts of pianism known to me, when you know what’s to it.