Well, it's not exactly THAT hard. You don't need to be fully maxed out, but at least have most of them in the 70-55 range. It took me about 8 minutes.
The Monsters I used were Flanitor (MED) 3607 HP. Golden Chocobo (COM) 5372 HP. Munchkin Boss (RAV) 4054 HP.
The Stats of My Team were as Follows. Noel: ATB 5. Strength: 424. Magic: 310. Equipment: Kaiser Knuckles. Commando 73, Ravager 60, Sentinel 44, Saboteur 48, Synergist 44, Medic 38.
Serah: ATB 5. Commando 57. Ravager 73. Sentinel 46. Saboteur 32. Synergist 49. Medic 50.
Flanitor: ATB 4. Medic 40. Abilities Cure,Cura,Curasa,Raise,Cheer,Esuna,Esunada. Magic 631, Strength 454.
Golden Chocobo: ATB 4. Commando 20. Strength 572. Magic 397.
Munchkin Boss: ATB 4. Ravager 30. Strength 279. Magic 667.
With this team and equipment, I finished in 8 Minutes. 5 Stars.
There are three stages to this fight. Alone with Lightning, Lightning and Amodar, and Lightning by herself but much stronger.
I would recommend Paradigms: Mystic Tower,Diversity,Tri-Disaster,Cerberus,Combat Clinic, and Protection. You should start with Tri-Disaster. If you're a little health wary, switch (Rav,Rav,Rav) to (Rav,Med,Rav). The key here is to stagger them and use Cerberus to inflict as much damage as possible.
Now for what to do. Starting with Tri-Disaster, the first Lightning fight should really put up a fight. Just stagger her then take about a quarter of her life, then the second phase appears.
Lightning and Amodar are a tough pair and will take a little bit of skill. If you're health is Below 3500 on either characters , start with the Paradigm Protection. A Sentinel will attract any damage and a Medic will be healing the party while a Synergist Buffs your party. After you're buffed, switch to you Triple Ravager Paradigm and stagger AMODAR as soon as you can. He is the most dangerous with his Buffs, Potions, and Saboteur abilities so stagger him around three times using Tri-Disaster and use Cerberus during the stagger.
If you need to heal, Diversity is a good all-around Paradigm. For emergencies, use Salvation or Combat Clinic. Try to get Smite or Noel's Finishing Move just before the Stagger Period Ends. No matter what you do, if you stagger one of them, they will go into Double Dose (Med,Med). THis is your chance to buff your party, heal them, and also using this precious time to build up the chain gauge as fast as possible.
After Amodar is down, Lightning is alone. When you see her use Limit Break, regardless of what you're doing, go into Tortoise if you have the Paradigm. She will inflict massive damage on one enemy possible killing them with Low HP, so keep those Phoenix Downs ready. By now you have all you need to make them into Monster Crystals. Hope this Helps!