First: no, 16th level is not too bad. You can finish up at that point.
Second: to get more experience, do every quest you can see, explore everything you can, kill all the big nasties you can find. Leave no stone unturned, no nuetral untalked to and no monster living.
Third: It's not that hard to max-out your exp by chaper 7; keep your party as intact as possible, swapping in other characters only for their side quests.
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WizWom - Wandering Kernel of Happiness
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