This looks interesting. I only gave it a quick glance now, but I'm definitely coming back to give it a more throughout look later.
So far I've kept my players one level under where they're supposed to be at (I don't give them exp I just tell them when they can level up) which usually works fine as the group is usually at 6 players (sometimes more) and I'm way too nice, was quite the challenge the last couple of sessions though when I only had three players. They did prevail though, barely (I was nice).