Ideal Damage Dealing Party for bossing like horntails, zakums

30% DEF FROM ACCELATOR

Accelerator works on bosses?

60%DEF IGNORE , 50%DMG + 180CRIT Damage for Siege Mode

150% Critical damage average, actually. Also, give other party members some credit, it's not like the Mechanic will do 51% of the damage to the boss.