Try a few things for an hour each and see what happens...

1) Questiong, solo grinding, etc etc (this is probably not the best choice)

2) Boost with one mage (I think this might be the best choice).

3) Boost with ALL FOUR mages (or maybe 3x mages & holy nova priest) (This might turn out interesting...)


The XP per kill with a lvl 70 in your group is not a well known formula. I wonder if 4x 70 & 1x boostee would gain around the same amount of xp per kill?

If thats the case.....gather 10-20 mobs AE, rinse repeat. You would annihilate everything. If case 3 gives you good xp/hr I would definitely go with that. You could boost with 4x mages all the way to 50 I would imagine.