It's been few years since I did my 2, but I don't think they've changed it much. It's less an exam and more of a continual assessment over the 5 days. You will end up teaching a lesson that's your "evaluation lesson" but they look at the teaching you've done over the whole course, so there's some leeway if you goof a little. Typically the lesson won't be very long, usually 15 mins or less, you get time for a quick assessment and a drill to develop. Once the examiner sees what's needed, he'll usually cut it off there and ask where you'd go from there. I've also seen some examiners give a second shot to some of the group who didn't do as well, if there's sufficient time (obviously this depends on the examiner, group, and time, so don't count on it).
I wouldn't worry too much about the 2 teaching. It is a big step up from the 1, but they give you everything that you need to know on course, and they should tell you fairly clearly what they're looking for. It's not that hard to go in cold turkey and pass (I've known several people who have done it without any previous teaching experience aside from a level 1 csia or cscf).
Having said that, by all means work on your teaching, but I would strongly warn you away from choosing a fixed progression for each of the possible lessons. Know some useful drills (multiple ones for each incase somebody uses the one you had in mind before your turn), and have a general idea of progression. Examiners don't like to see people teaching a pre-planned lesson, and if they think you are, they'll likely throw a wrench into the works in order to see if you can adapt.