well firstly i concentrated my attacks on the little 1 cause her passado is a devasting move cause its gravity based. she has about relativly few hp,about 10000-11000 i think . her evade is pretty high though so its probably best to chuck your best skills and magic at her.

switch to special dress sphere after a while before they use delta attack to protect your characters. i recall just using powerful warrior tecnigues, black mage and great whirls. not a great technique i know but u can fudge through as long as u take out the little 1 asap.

but yeah killing the little 1 is the key, after that they become so easy its funny.