That makes perfect sense about not being used to the rental bike, but I think I'd be more comfortable pushing it on a bike that's not mine (I assume you have to pay for insurance on the rental of some sort?). I like the idea of the track day school, that sounds like the best place to start. It's not like I jumped in the ocean the first time I put on SCUBA gear! I've also read that you can rent leathers at some places, even so, would you recommend getting my own to assure that they fit?
i hired a bike last time, didn't sit on it until the first session and sighting lap. jumped on it an immediately dislocated my hip slightly as i wasn't used to it (it's just uncomfortable, not really painful). also wasn't used to the back brake position so didn't use it at all
jumping on my bike afterwards was very strange, handlebars too high and pegs too far forward
rental bke cost around £190 at the time, which included tyres, fuel, tyre warmers etc, and it was a nicely set up cbr600rr.
i'd recommend getting your own leathers, if only so that you wear them when you are riding normally! :spank:
i bought a set of dainese ones and i love them to peices, if you're on a budget then you can probably get some nearly new ones on ebay
my first time on track was at a school, they taught us the correct lines etc, and slowly built up through out the day, for that they made us use our road bikes, and it was a very safe environment (nobody fell off)
i know you have the CSS over there, but there's probably a few cheaper alternatives