g'day PianoStrawberry,
I hope someone else can answer your question about which Chopin Etude to start on.
I spent about a year on a handful of them (must have been almost 20 years ago), mostly from op 10 but not #12 revolutionary. I started off working on double notes, plus the Rakhmaninov double notes prelude from op 23, and the Czerny Toccata. At about the same time, I was also looking at two of the left-handed Godowsky etudes: no 5 based on op 10 no 3, and no 13 based on op 10 no 6. The left-handed etudes were good for me because I had to really think about pedalling and listening to the sound.
Every one of the etudes I tried was "hard" for me, but I definitely got something from my lessons and from having a go. I never played any of them up to speed, just a better appreciation of the piece through getting to know it. I have recently discovered the Cortot edition of Chopin's and Liszt's works and I find the preliminary exercises interesting and helpful (for pieces I had tried previously).
PS I am currently reading "Ignaz Friedman - Romantic Master Pianist" by Allan Evans. There are about 3 pages on the Chopin Etudes from an interview with Mack Jost who learnt with Friedman. You may want to dig it out from a library for a quick read. But it does not cover the Revolutionary.