I got about a 2-3 weeks notice, but I booked the day off work because I wanted to watch it all and didn't want to be distracted.
Forgot to say, any questions on anything specific feel free to ask, there's a chance it was asked and answered. I managed to make made quite a few notes from it - there's too much to write everything here though!
I'd say about half of it was probably stuff you'd already know if you'd read online so you didn't miss tons, but it was still useful for some of the tips and it was very helpful of them to put it on. Last time I applied (when Covid wasn't a thing), I was able to attend an OASC prep day at my local OASC, so I suppose this was the current equivalent. It also covered the whole application process however (CBAT + OASC) and not just OASC, so for those of us who are later in our application process, not all of it is as relevant (still interesting to listen to however).