I just got the Earth Crystal and for the most part it was easy. Refia goes from Monk to Black Belt, Arc goes from White Mage to Devout, Ingus stays a Knight. But Luneth has been a Black Mage the entire game and I figured I'd just upgrade him to the Magus, but the Sage can learn Summons too and the Summoner is just a straight up power house, so now I'm leaning towards those two over the Magus. So what Black Mage class should I give him?