Henne is pretty simple leveling, i got my main 3, Vaan, Balthier, Basch,(in the name order 92, 88, 87) to level there several times, at least the phase 2, and and my weakest Penelo, Fran, Ashe (in the name order 38, 34, 28) can be trained in phase 1, i feel pretty good about Henne mines, overlooking eternity is good because of loot and amount of enemies, but its a 50-90 place, Henne is a 20-50 and a 70-99 place, for 20 levels you could leave, but going to the pithead junctions, pulling the lever or w/e does get the Jelly things to attack you from outta nowhere, and its like 20-30 of em that drop, so an easy 20000-60000 depending on level and if you have the x2 xp thingy on. also really good loot and a 15% appearance treasure with 10% for a Zodiac spear in Phase 2, so kinda nice, also Zodiark is in there(most pwerful esper)