In the Book, "Chopin as Pianist and Teacher," ed. Eigeldinger, there are several examples of excerpts from his music where Chopin added variants for his students, which may be interesting for you, and I think a few words from Chopin on a few of his pieces, though nothing terribly surprising.
One time the old-time pianist Vladimir de Pachmann played for Liszt and Wagner. Wagner said he would become the greatest pianist of all time (that proved not to be true), and Liszt said that de Pachmann played Chopin's works better than Chopin himself, adding that Chopin frequently played in a very mannered style.
Walter Ramsey