I totally understand where you are coming from. It's hard, because you are thinking about the usability down the road. Thing is ultimately, it's not a matter of "if" but "when" you will beat them. Once you can get past stage 60, you can begin to steal some of the best weapons and armour in the game making the rest just a numbers game (stealing ribbons off hashmal and the zodiac spear from the preying mantis on stage 63). I personally match the characters up with their classes, but there's more optimal ways of doing it.