I found the greatest leveling/lp combo is get your main party with embroidered tippets so they get double LP whilst travelling, then get your reserves with golden amulets so they reap the license benefits. Walk from the henne mines to golmore jungle and back through to the tchita highlands and stomp malboro overkings or saurians. have one character in each party (main and reserve) set up with a steal: enemy HP 100% and make that person party leader. they'll snap at the enemies first, stealing before your beast of a party kills them off. swtich at whatever interval you choose. you'll be swimming in gil/exp/lp in no time.

my avg party level is 52 and I'm not even to old archades yet.