Also, remember to convert them to fanatical using your near epic diplomacy. It may only be a +2 str and con and +1 to willsaves, but it also renders them willing to follow ANY order you give, even without magic.

You just have to diplomacy them to frendly and hit a DC 60 diplomacy check (this is also a good way to talk them into doing the whole level drain rebuking to be your magic servant thing). They stay fanatic for a number of days equal to your charisma bonus, and you are a +4 race, so after book and cape, you are looking at an easy base 15... So you end up with a charisma of 30, so 10 days.

Also, this means your base diplomacy is 20+3 ranks +10 charisma, so 33. A single guidance of the avatar puts that at 53, so take 10 and you hit 60.