The high level CAN be linked to get raf bonus. You just need a link involved where both recruiter and recruitee are within range of the xp.
So booster->acc1->acc2 will work because they get the bonus from the link between acc1 and acc2.

As for using a lvl 80, it won't change the xp at all. You won't get any less xp but it should go faster with better stat, spells, and gear.