Les Adieux, of course, but you have specified "1st mvt.". IMO, If you have played Chopin's second Scherzo you are technically in shape to play the whole sonata, specially the third movement, wich is the core of it.BestAlex
I disagree. Opus 81a is a beast, and the third movement is enough to give you tendonitis! The 2nd Scherzo is in no way the same difficulties as 81a, and I wouldn't recommend it to you if you don't have time for two big pieces. I'd recommend the D Major sonata you have listed, it's much more managable.