Efficient LHC Training?

While I don't know of any guides for it, the general idea is to deal more damage than everyone else while still having a strong party to back you up. Having a Priest for Holy Symbol is a must, and then using a 1.2x exp buff is also necessary for achieving the highest amount of experience. Just remember try and find a party that's powerful enough to kill each monster in an relatively short time frame, but with no members that are as powerful as you.

Of course, after the party experience division is put back to how it used to be (60:40 ratio), the only thing you'll need is an excessively strong party and a Priest.