(my first post!)
I started working on this piece pretty recently, since about the time this thread was last visited (over the holidays), as my main "getting back into piano" piece (I've played on and off over the years). It would be very, very tricky to learn it by ear, because of the multiple voices and figuring out exactly what notes to hold over, etc. It certainly wasn't obvious from the recordings I analyzed, anyway. So kudos to you for being able to do that!
That con bravura
section is killer (my first reaction on reaching it in the sheet music: GROOOOAN... tooooo many acccidentalllls!!!!!) It was much easier for me to learn it by ear--what I did was recognize its basic "algorithmic pattern" (paired in leaps by tritones, generally chromatically descending, etc.). Despite knowing that intricately, I still play it with a lot of, as Damon would say, klunkers. It's improving, though, reasonably klunker-free at 3/4 speed, I think. It'll still be some time before I can share my results here
All the recordings I've analyzed have slight pauses in between each middle section theme, like, for example, right before the section with tritones. I naturally have long pauses there because I'm still simply just taking too long to figure out where to move my hands
but I do feel that those short pauses make sense, despite the sheet music not indicating it.
But yes, thanks for sharing... it is good encouragement to stick with it, and inspires me to get it to performance quality!