I soloed the enemies that dropped the testimonies, but I never had enough MP to spare on nukes since they hit rather hard, even at 75 and with slow/paralyze/etc. on the mob. That said, I didn't have /NIN with both utsusemis so only having blink for shadows made me need to heal much more often since composured stoneskin only had so much protection before it broke.
I could probably beat him now, I got 99 RDM before I quit FFXI (level cap raised after Abyssea expansions came out) lol. Maybe I should resub to XI for a month just to beat him xD.
EDIT: Yeah I probably could beat him as 99 RDM if a 99 BLM can 1 hit Maat xD http://www.youtube.com/watch?v=Zib2Atv_eHc