Here's how I did it. Two characters with Master Summon (Yeah, I'm a sucker for punishment...), and one designated healer (W-Item may help on him/her). I had only one W-Summon, so I had Cloud W-Summon Hades/KoTR, or KoTRx2 if he's still paralysed, and the other cast Hades or KoTR as needed. Have the item master use a Megalixer, or attack, if you so desire. Battle ended in fairly short time.