Simplest way to mark distance before a charge?

[vartan]

I've been able to charge in the plaza, given enough distance. You'll need at least a large town if I'm not mistaken, along with the right moves/positioning. As for the simplest way to mark distance: experience. Given enough experience (read: practice) you can almost consistently nail the charge distance to lower lances.

[Ludens]

Another thing that can mess up charges is pathfinding. Your units should be no wider than the actual street (the pavement) or else the engine will continually try change the depth of the formation. Street width can be hard to guess in barbarian towns, but is actually the same as in civilized towns, so just use the same unit width there.