This is totally unnecessary - I just beat the game and my highest level was 48.
Really, people seem to grind way too much in this game. I think I beat the Feywood with my characters around level 36-38, then I finished the Pharos at Ridorna at 41-44 or so. The key to this entire game is offensive magic, especially stat inflicting spells (slow, blind, silence), which is actually effective for the first time in the series. Almost all of my boss fights ended up being edge-of-your seat, just as I like it :D.