Any tips for preparing?

I found getting teammates to sit in the server with me and analyse my driving / give me live feedback was really helpful! We would rotate and give feedback to each other. Often it wasn't just what they were telling me, but the fact I knew someone was watching made me more focused on what to improve.

This is probably too specific to be helpful, but because the VEC had 3 divisions at the time, in the few days before a race the practice server would have 70-80 cars on at peak times, which was absolute chaos. That was pretty useful for practicing traffic, for sure! But any way to practice with real drivers definitely helps.

It’s one of the things I love about ACC with having to deal with rain and so on which can really mix things up

Definitely, I love how dynamic the sims are getting and hopefully this will keep getting better across the sims! It makes it much more interesting when there's a bit of rain in the mix :)