I do the previews later to leave more time to do position switches. If the majority would rather have them done sooner, I can do that. My threads are pinned because I asked CS if they would do it and they thought it was a worthwhile contribution, not that it generates a lot of posts.
Regarding timeliness, the process is automated but I still rely on other coaches to remind me when worlds are ready. This is something I do in my spare time. I'm not paid to do this or otherwise reimbursed. I work them into my schedule, along with three full-time jobs: being a parent, work, school.