Honestly I dont really know when I should CP farm. But im gonna farm 10,000CP before going forward. Im gettling 120-160CP per battle right now fighting those Rescue Flans. So it may take a few hours to farm 10,000. But those Green Flans are easy to stagger because SLASH AND BURN usually works well against them. I could fight those Porcupine looking things but they may be too strong for me at this point.
Favs: Xenogears, Phantasy Star, Star Ocean, Arc the Lad, Tales of Destiny 2, Suikoden, Final Fantasy Currently playing: Eternal Sonata, Graces f, FFXIII
Chapter 7 is really way too early to farm CP. If you aren't passing battles up and just travel through the game normally, there is more than enough CP. If you're really set on farming CP, chapters 12 and 13 are much better for it. The most ideal time though, is after the story as that will be when you open up the crystarium fully.
It is never really worthwhile to farm CP unless you're also farming decent components. Flanitors do not drop decent components. As noted, if you just fight everything in your path, you'll do just fine with keeping up on the Crystarium. If you must get ahead, I recommend waiting until later in the chapter, when you'll have two fights against soldiers in an enclosed loop with a better party than your current one. The fights will respawn by running around the loop, and the soldiers drop stuff that is worth decent gil.
Chapter 8 is terrible for farming. Chapter 9 has a few decent spots but nothing special. Chapter 10 has a fight against 4 Circuitrons that yields decent drops and is easy to respawn. Chapter 11 has a tunnel in Mah'habara (see the Ch. 11 thread). Chapter 12 has some decent spots but nothing standout. Chapter 13 has the Sacrifice groups right at the beginning for arguably the best Gil grinding in the game. Once you've reached that point, you want to prep for Adamantoise grinding in postgame, which is comparable Gil, better CP, and has a superior catalyst drop.
The only spots mentioned that are truly worthwhile are the Ch. 13 Sacrifices and the Adamantoise. Next best is the Mah'habara tunnel. The other stuff is for power gamers only, since even "large" CP gains before Ch. 11 are rather small compared to the Crystarium costs in stages 8-10, and the gil/hour is miniscule compared to Sacrifices/Adamantoise.