While I don't have any certain answers (which is why I didn't reply earlier), I can make some educated guesses.
Regarding the time, it's been on Friday the past two years; the timing and length weren't exactly the same, though, as I recall, so there is already precedent for it changing.
Regarding clothing, I'd guess that anything not too extreme should be okay. My impression is that ideally it should be something that you feel good wearing and that's pleasing to others to look at, in that order, and of course not something actively hostile like a T-shirt covered in insults. Maybe something more daring than you'd usually wear, though, if you think pushing that would be good for you. Pony-themed to some degree would probably be good if it's themed at all. Again, though, this bit is guesswork, and I'm far from an expert in fashion; sorry I can't offer more.
Have you attended as an audience member in previous years?