Good luck in your journey! I, too, was originally planning on the band. It was after my initial orientation class that I started to consider the sleeve.
I don't yet have a date. I'm waiting for the schedular to call me. My surgeon is really booked and I've heard they are scheduling two months out...so I'm probably looking at early December. No pre-op diet other than a very light meal the night before surgery. I had to lose 30 pounds before they would even submit to insurance so I think that's why there is no pre op diet. The only thing I'm doing to prepare is getting in the best possible shape. I walk hills 4 days a week and I swim at least 3/4 of a mile two days a week. I can't wait to really start training for my first triathlon which is late June of next year!!