For me filling 8 hours with stuff I desire wouldn't be hard whatsoever.
I have soooo many kinks and fetishes that i'm very into that the only limit would really be how many different activities the domme would be willing to do in the allotted time!

Even if I was limited to just 4 basic fetishes I would easily think of ways to fill that time because of how much fervor I have for domination.
Like being used as a footstool for a domme while she watches an entire movie wouldn't bother me at all.

Pro domination in America doesn't really seem conducive to long sessions though, so you probably have the right idea with just half an hour session.