1. Disable Gafgarion. Obtain a thief with the appropriate Zodiac sign for best results.
2. Disable Time Mages. Height+Prime Number works, or Agrias's Stasis Sword or Lightning Stab, and pray for a Stop or Silence bonus.
3. You must have high damage characters to mop up the remaining battles. I had a Monk with Two Swords and Revive, a Ninja with Guts, and a Minitaurus my most recent time through, and thoroughly destroyed the battle. Of course, the Calculator and Thief helped too.