One thing about the original addon that I love is that you can put in the max number that should spawn for that group of NPCS. So you could have a consistent 10 combine and 20 citizens.

The max NPCs slider isn't very clear and changing settings for each NPC group doesn't seem to do what I want.

If I wanted to spawn one of each zombie, I would end up getting multiple normal zombies, no fast zombies, and vice versa.