I don't think i bothered with overdrives at all (not even wakka's).And that's because if i used an overdrive Penance turn would come quicker.Instead i kept hiting him with quick hit.
I had the celestial weapons of course and armours with auto-life,auto-haste,ribbon and break hp limit.
Also all stats were 255 except luck which was around 200 (if i remember correctly).