@ Broken Heart
Well i am not really the wise man as far this game, but you said you were having easier time fighting Emerald. so why don't you concentrate on defeating it/him/her/whatever and then obtain the Master Materia set by exchanging whatever he drops with the kalm traveller. So that way you have the Master Summon which i presume will include KOTR and Master Command, which again will grant access to Mime, and then you can follow the countless strategies already suggested. I can't say much, I am still trying to defeat Weopon on my relatively 65-70 levelled characters (with strength's 93,76,75 for my characters!!!! I know this is suicidal! but i managed to deplete around 6,00,000-7,00,000 of its HP therefore i am a little confident) . Though somehow I too feel that EMERALD is a lot easier, cuz i dont have Mime and therefore am dependent a lot on limit breaks and EMERALD's low defense (RELATIVELY OK?) makes my job easier as i am more of a hack-n-slash player. I just hope that the their is no flaw in above strategy cuz that's how i hope to defeat the Ruby Weopon whose high defense irritate me a lot!!!)