I don't know what character to play.

I'm actually thinking this. I can just fund multiple classes and have them all there for when I want to train/boss etc. I usually like to boss on my Phantom and Night Lord and then train on my Outlaw and soon Dark Knight I hope

make characters that are capable of bossing without too much funding, i.e mercedes and blader.
then move on to jobs that require a bit more
and so forth

prepare yourself for luminous, kaiser and buster - they're all very boss-capable.
my luminous friend has 78k mp at 194 or something, and washing doesn't exist anymore iirc.
kaiser has crazy HP but no statres/avoid, but they can tank like hell.
busters are just crazy.