The cheap way to beat him is the mime method. have one character use bahamut, meteo or $toss ect and just mime it over until you need to stop to heal, then just do it again.

the part at the very back of him is the one you should kill first because it has his most powerfull attacks. for inflicting the most damage on it, throw a magishuriken (over 7000 easy) then mime till its dust.

also, equip the right items coz this can be the difference from life and death. equip four winged shoes because you will have haste2 active as the battle starts so all four players are garunteed first attack (and usually a few more before he attacks so you can kill tree x-death before he even moves.) this is also a good way to put up a super defense before he can attack.