I've been using Team Magic (Hope/Sazh/Vanille) with Hope as leader. Got a pattern going to kill the Sacrifices at Ch. 13. Only focus on the 4 pack, and don't settle for anything less but a PS. You'll just waste time if you fight a non-PS set. If you don't PS, then just select retry and wait for all four of them to turn their backs. You'll want to focus on the lone one that wanders on the back side. The battles go like this:
(Always switch to the next paradigm every two turns, to get the bonus full ATP bars.)
Hope/Sazh/Vanille
Syn/Syn/Sab (Superiority) - Cast Haste on your self (just auto-turn), then cast Quake quickly to keep the stagger bars from dropping, switch during the animation
Sab/Syn/Sab (Espionage) - Manually cast two Deshellgas, then one auto-turn, switch after your bar is out
Sab/Syn/Sab (Espionage; dupe) - Two auto-turns, switch again
Rav/Rav/Rav (Tri-diaster) - Two auto-turns, switch again
Rav/Rav/Rav (Tri-diaster; dupe) - Two auto-turns, switch again
Rav/Sab/Rav (Smart Bomb) - Two auto-turns, switch again
(Everything should be dead before you even get to Smart Bomb.)
The idea is to have deshell on every Ce'ith as well as stuff like poison and imperil. By the time you get to Tri-diaster, you will all have haste, and probably have fire element on your weapons. This usually takes 45 seconds. Even if you aren't getting times like that, just keep fighting for CP. They give great CP with the Growth Egg (which you should be wearing, anyway). Other items you should have equipped are the Collector's Catalog and Shroud Catalog, to get the 12K perfumes and sometimes some Decepisols. Don't use the Connoisseur Catalog, as you want the 12K perfumes more than the 7K Scarletites.
After you are finished with the battle, go to the ramp at the bottom at about the 3/4th mark down. You will see the dots reappear. Go back and kill the 4 pack again. Rinse, and repeat. One cycle takes about a minute 15 seconds, with about 20K gil each pack. This nets you about a million gil an hour.
Occasionally (every 15 minutes or so), take a breather and go to the save point. Sell your perfumes and Scarletites for good gil. Buy reactors and upgrade your weapons with Exp 3x Reactors. (Don't forget to save before any upgrades to make sure you don't waste any of those.) Use Tier 3 maxed out Marboro-based Nirvanas to disassemble into 3 Trapezohedrons. (You'll need to buy your first one, but don't buy any others. Just put one into a Marboro Wand and disassemble it when maxed.)
Do NOT stop to beat the game! The ramp won't be there, and it really blows. Don't worry about maxing our your CP Stage 9. Just keep at it until all of your weapons are maxed out. You might even want to get some dark matter afterwards.
CP is easy. There are 6 cryohedrones on the "secret" area of the Atomos underground area. Kill those, go back a ways, repeat. Again, Team Magic on Tri-Diaster works well, with forced Firaga commands.