Listen to Ultima Shadow. He's the best when it comes to doing creative, demeaning things to superbosses.

There a number of creative ways to beat Emerald and Ruby; no materia is one of the best. If you're going after Ruby without materia, I strongly recommend you have quite a few Dazers items in your inventory.

Including materia, of course, allows for you to do horrible things to Em and Ruby. My goal on my next FFVII playthrough will force me to leave them until I've done a lot of materia leveling, since I hope to destroy them never choosing an action (in other words, solely through countering).