It is tough though I feel IV is a bit harder since it literally throws you to the wolves with a party set-up that seems to be crap at first...

I'd play with the job classes more and make sure you build something balanced. Though there are battles where transforming everyone to a single class is the best way to get out of a battle. Also, don't overlook classes like Bard and Dancer, they smurfing rock in this game. Play with class combinations and play with the equipment a bit.

P.S. Why the hell are you not playing the superior GBA version?