[Micah]

I believe this is how it works:

Prophet spread = 1 temple check per turn

Heretic = Priest of x level preaching in the province against dominion. Which is (30% * priest level - 5%) per candle chance of knocking the dominion down. According to the rulebook, which is often wrong. So a minor heretic prophet should still spread a bit of dominion on average, depending on domstr.