[Saber Cherry]

IIRC indy level 3 is the default, and the higher the number, the more powerful independant provinces are (roughly log 2 according to Illwinter). At 3, there might be 15 militia in a province; at 5, that province should have more like 60 defeners, and possibly a mage; at 9, the indies can have large armies that sometimes include non-declared Gods, like Titans and Earth Mothers. I like to play at 8 - at that setting, there are occasional indy provinces that remain until the late game because they are too strong. Triton provinces can get pretty crazy, though.