Note that only New Threads will appear in RSS data feeds, not new replies to existing threads.
Also, only New Threads in forums that are accessible to Guests will be included in the RSS feed. The reason for this is that an RSS Data feed is not a real user and has no user account on the forum. By its very nature, it is a guest that can pull data only accessible to Guests.
As the forum is setup now, not much is accessible to non-forum members (Guests).
Not what you wanted to hear but at least you'll understand why you won't get a lot of data via the feed.
All that said, it's what I learned tonight from reading on the vBulletin support forum - not from my own experience. So we'll see if they are right
Jim