I do a lot of grinding for magic and such in the games to ease VIII's difficulty (not that it's hard). I've never really tried for any of the ultimate weapons/limit breaks until Disc 3, though. That's when it is easiest to get those things, and the only time I ever used card mod was on cards I got from beating bosses (like the Bahamut card, I think). I only ever played a lot of Triple Triad because it was fun. I've considered doing the Lionheart on Disc 1 thing, but I think I'd get bored at that point.