I'd ungroup the Paladin and just do quests.
Tag everything, and have the shaman's obliterate it.

You're within 10 levels, so you get 100% of the experience for mobs you tag.
If there's an 11 level or greater variance, you only get the portion of experience of the percentage of damage you deal.
71-61 = 10.. this is not an issue for you.

Quests will be insanely fast, and you'll get 100% of the exp's for kills along the way.
Don't think you'll beat this in an any instance, grouped with 4 toons 10 levels higher then you.