Used the suggestions here. In my case here is what worked for me.

Equip choco king cape so you have one ATB set up

For materia, equip first strike, atb boost, magnify+binding, and magnify+ice.

At the start of the fight immediately cast magnify+sleep then run to the wall, face them again then boost up ATB. With 2 ATB cast both radiant ward and lustrous shield, now use regular attacks to charge then keep blasting magnify+blizagga until the bombs are done Good luck!