What do you fight? I mean, I know there's the Adamantoise what with Vanille doing Death but it can take some time before you get much success, even when using equipment to encourage drops. I think there should be a more accessable final weapon upgrade item. It's taking me forever just to get one of these suckers, let alone the amount of gil I'll need to upgrade a final weapon to maximum. I imagine once I get 2-3 done (probably by doing Fang's weapon with my first Tezawhatever and then dismantling it for three), Adamantoise might be much easier, but at the moment I've already maxed out four roles for each of the characters and I'm still not getting money in much faster.

I'm thinking I might go and fight those white Cie'th (I can't remember the name off the top of my head) in Eden for some time instead as their drops come a bit easier and I'm not relying on luck like I am with the Death spell.