Get the mime materia and use it to do many omnishlashs or master it and use it to use Kotr.
there are heaps more but i cant remember them
Final Fantasy 7 has this AMAZING (not at all cheap btw) materia called W-Item. There is a way to duplicate your items. Presumably (hopefully), you know how to do this. Make 99 Elixers by the W- Item trick method. Go to the Northern Cave and encounter something called a Magic Pot. It was ask you to give it an elixer. If there are 2 magic pots…give them BOTH elixers. NOW then. After you give them an elixer, kill them. They will give you the most AP found in the the entire game. You can master ANY materia within hours by doing this.
Of course, through this method you can master 3 Final Attack Materias, then equip all three (paired with revive or Pheonix) to your three characters so that you never die versus Emerald Weapon or Ruby Weapon.
My final hint is that Equip Cloud with something called Mystile (or something like that) and he will have a 98% chance of dodging Ruby Weapon’s Ultima, so you can cheeze away with Knights of the Round and he will miss with his brutal counterattack known as "Ultima". Also having the mastered Final Attack paired with Revive makes Cloud vs Ruby Weapon a one on one piece of cake match.
Why waste time killing the other two members and reviving them when you dont need to? Don’t waste your time doing that. Just beat his ass with Cloud. You don’t even need the Ultimate Weapon.
Enjoy. Au revoir.