[quote name='Azumangaman']Dang, I hate Mysterious Unison so much. My party (Jazz, Viola, Falsetto) are lvl. 60, 59, 60 and are getting destroyed (only on the 2 floor). I need to get used to Party Level 6, I HATE when the guard and attack buttons change sooo much.[/quote]
If you're having trouble, I'd recommend switching out Viola with either Polka or Fredrick. While you do some extra damage with Viola, it isn't enough to offset the fact that, at best, Heal Arrow restores less than half of the potential amount that Fredrick's or Polka's final AOE healing technique does. Equip Tyr's Left Arm (which increases combos), your Werewolf Choker, and that item that gives burst status to Falsetto, and you should have enough speed and be able to deal enough damage to take out one enemy at the start of each battle. You can either use your healer to deal some extra damage, or have him/her run as far away as possible and use an AOE damage and healing special, whichever your preference. Just don't miss any guard opportunities and hope your healer doesn't get ambushed from behind, as battles start to go south rather quickly once you're stuck playing catch up (as you already know).
A good way to build experience on the early levels is to only fight the dragon enemies, as they're a lot slower than the bandits. Falsetto should be able to take out the first dragon at the start, and the other attacker in your party should be able to take out the second (after it attacks). Your two main attackers should be able to set off a harmonic chain every turn, unless they're attacking an enemy on the other side of the field.
I started out the Mysterious Unison with a party of March, Viola, and Falsetto at around level 50-55, and ended it with Jazz, Polka, and Falsetto at around level 75. The hardest boss is on level 12. If you can get through that battle, the final boss shouldn't be any problem.