Using two Blessed Shields with Group-Cast All, a White Mage with Big Pharma/Dark Cartel and a Knight with an ax, I was able to literally farm all night without worry of dying.
... I woke up the next morning after leaving it on, and I had 3 million pg... I mean, yeah it's great because now I have a ton of Dark Banes and Shadowflares, but I mean... It feels cheap.
You can farm that much in like an hour later on in the game - check out Obliterate on the Jobs FAQ. Just slap on a Golden Egg... pew pew... get all the bonuses every time. Luminous Robe + Glitterbug x2 also lets you farm mindlessly in Ch.5. There's a Ch.4 farm, but I remember it not giving me Sweeper every time.
It's easy to farm, just keep your own pace. The Nemeses and the last chapter bosses are pretty cheesy even for a 99, so you're not breaking the game! :3