One of the changes on the DS FAQ is a piece of errata for page 76, explaining the numbers of Commands per turn and Command cards the Overlord has. Some folk have found this a bit contra-intuitive, but it is correct.
The confusing bit seems to be that the Overlord gets more Command cards against inexperienced opponents. That’s because the cards are the game’s timer, so more cards means more time for the neophyte Heroes to make their way past the Overlord’s minions.
Commands per turn works the other way, as this is the real danger to the Heroes. Here the Overlord gets the ability to do more against higher level Heroes, to balance the game better.
However, these are just guidelines. The number of Commands per turn is particularly hard to make fixed rules about because it is so sensitive to things like the layout of the tiles. You’ll note that the pre-written adventures have a much wider range for Commands per turn than mentioned here, and this is because they’ve been balanced by repeated playing.
When you design your own adventures I’d start with 3 Commands per turn as a starting point and see how that goes. You may find that the layout makes the Overlord’s job easy, even if he doesn’t have that many minions. All sorts of things can impact this balance, such as the type and strength of locks, width of corridors, number of doors and so on. And that’s not to mention the combination and levels of Heroes and the relative skills of the Hero and Overlord players.
All told, you will probably need to be prepared to adapt things to suit your player group if you want every adventure to be perfectly balanced. I will be adding another article on balancing quests to offer some more suggestions, but the fundamentals aren’t going to change. There’s no way to make something this flexible into a hard and fast universal rule (that works). That was always going to be the downside of having a system that allows so much mutability 🙂