After you get the growth egg from mission 55 you start to gain CP very quickly.. I think that it only took me about 2 hours to max out all of my players standard roles, well for there last role level anyways.
the three people i mainly use is Lightning, Fang and Hope
I use hope as a ravager and synergist. The whole time i have been levelling him up i have been mainly concentrating on magic, same with his accessories. he is on around 2000 magic with only about 800 strength.
U use lightning as a ravager and back up commando, so her strength and magic is around equal to eachother.
and i use fang mostly as a commando and sabatour, so i have concentrated heavily on her strength..
as you level up u find that it splits off into sections which usually cost more CP.. if this was strength for hope then i would not bother.. Basically you have to choose whether things like that are cost efficient early one. When you are earning 40000 CP per battle it wont matter to you as much.
I’m making Fang into my main ravager/support commando/secondary sentinel;
Vanille is my main Healer, I might make her learn some synergist abilities;
Hope is a reliable healer and one of my best synergists;
Sazh is another commando and synergists, I’m not sure what I want to do with him though;
Snow is my main sentinel and another ravager/commando.