Levelling with help question?

A levelling question here slightly different from the others hence the new thread.

My pally is 42 and prot at the moment. I have 3 70s already so I would like to just catch him up to 60+ as quickly as possible. I see three main options:
a) stay prot and quest up
b) spec ret and quest up
c) borrow a friends holy pally to heal me out of group and aoe grind up.*

*I have tried this and the problem is, I cannot find groups of mobs > 4 than I can pull without them tethering back to spawn spots. I think this would clearly be the fastest if I could find packs of 10+ mobs to kill per pull.

Any thoughts are appreciated.

If you want to level up that quickly, bring your friend's pally to SM or any other dungeon of choice and power pull the whole place, while you stand safely in a corner.
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WoW is a giant math problem, and you have the wrong answer.

If you're having leashing problems trying to gather up a large enough group over a large area, drop a consecrate or two (rank 1 is best) on them. The damage should keep them from leashing as they chase you around. Just remember that they have to go through it long enough to take some damage.