hi,

so i did a little bit of karazhan with my mixed group at lvl 68 with a boosting pala at 80. i think i got around 1000exp per kill (rested).
that is not bad, but i would only recommend it with a higher level booster because otherwise it will take too long to kill something and the danger to wipe is a lot higher.

maybe that could help you a little.

greetz,
dasvorbei