It's probably not of much use for this particular piece, but this is slightly reminiscent of the opening LH of Beethoven's Op 31 No 2 Sonata (Tempest), finam movement:In that case one is supposed to use fingers 5-4 to jump from D-A then hold down the A with the 4th finger.Maybe that sort of thing is intended here but I guess it's hardly practicable in view of the spread of notes and the speed and dynamics.
This is interesting! I learned this piece a few months ago. Well, I should say that I started learning it! I have a Henle Urtext edition which doesn't have the lengthened note you mention. I found that the best fingering for me was 5 3 1 5 1, and not releasing the 3 until the moment I had struck the last 1. I don't have a teacher so this might not be what is recommended but using the 3 as an anchor felt natural to me.I'd be interested in the strategies you found success with! I learned the entire piece and got over my obstacle of synchronising the hands during an ascending run. But after some weeks of practice I still couldn't play the ascending runs at a good speed, and I haven't been back to it for a while. Next up - Mephisto Waltz #1 hahaha.
Regarding those various “runs” written in small notes, I’ll share something that I found to help. Normally I would never use the Chopin editions of Karl Klindworth because they are so over-edited; however, for this prelude he suggests precise subgroups for aligning the notes of each roulade with the notes played by the left hand. Those exact divisions will obviously be allowed to blur (i.e., even out) when played at tempo, and this edition really made the whole synchronization process effortless for me. It’s available at IMSLP.