[thejeff]

Are you setting tax to 0?
Unrest matters mostly because it cuts into your blood hunting results.
If you're using Mictlan, using a few kings to hunt up slaves to patrol with it reasonably cheap and effective.
An alternate approach is just to take a turn off blood hunting when a province gets too high.

I think 3 hunters is a reasonable compromise between getting the most in every turn and not driving unrest up so quickly it shuts down the hunting.