ruby actually needs no special materia setup.no kotr,no ultima,no hp absorb,no what-have-you.all you need are dazers.get two people killed before the battle,then let the remaining one use dazers on ruby (and a phoenix down,if you have the w-item).when everyone's alive,hit ruby with whatever while he is still paralyzed (or stopped,if you may).when the status wears out,throw another set of dazers.use curatives when necessary.no problem at all.