How many people can watch?
The pack sets how many people can watch at the same time:
You can invite as many people as you like; the limit is only on simultaneous viewers. Someone counts while their page is open; after 30 seconds away, their spot is freed.
When it's full, a new follower sees "Full house" and gets in automatically when a spot frees up, if they stay on the page.
The limit applies before and during the race. After the finish there's no limit.