I usually beat the game before going for the superbosses. I can beat many on my own. It took me some time to find the second shop in the cleft town to buy more coral rings. I even equipped Ice Shield for Shinryu. I copped out with SShot against Omega.

Any boss dies to a 'calculation' effect in Tactics. Magic did make FFVI easy, even against its superbosses. With any other games it requires waiting for it in the end. Since I write my own games I know to make them possible to beat.