DRK has no BLM part they just have some MP. Their spells arent that important if you have a RDM or BLM in my opinion, so they arent as viable to rest after a fight when out of MP. You can keep on going and the best thing to do is rest after you run out of TP. Unlike PLDs(Cure spells are for hate management) and mages, your MP isnt that much on the high and needy list as of yet.

And BTW dont ever do a WAR/WHM, i seen enough of those to make me puke...its a horrible combo, the PLD wanna-be yet fails horribly.