since I first played FF1 in 1992 or 3, I think I've played almost every combination of classes from 4 the default party to solo theif and solo whitemage.
but my favorite and in my opinion best party, is Fi/Fi/Wm/Bm.
For the final fight, I usually give the Masamune the White Wizard, because she has to do something while she's not healing. The Knights do just fine with the Excalibur and the Defense?(haven't played in awhile) Sword. Then of course Black Wizard sits back and nukes Chaos.