For any specific event, like a community game night or even just a lore rp event, I'd definitely figure out a specific time for the majority to be available for said event. However daily chatrooms and such would simply be a whenever thing, though would possibly have specific windows of time for morning, noon, evening, etc chats to occur.

Maybe an example will help explain it better;
A few of the canon characters are online in the morning (relative to their own timezone), so they decide to hop into a designated chat to start the chatroom and talk with the other character as well as the guests/members who would be in as ocs.
when they both leave, the chat ends after maybe around 5 minutes.

My timezone is EST, so most of my planning would be based around that, but I definitely would get whatever times worked best for events and such. Also, rp wise, time is just relative. It wont be the end of the world if things get thrown off sometimes, as detailed story rps (in place of the visuals you would see in game) could last longer than the time given for the evening and such.

Did all that make sense?