ZM8 cleared with 75 RDM/NIN, 75 RDM/NIN, 75 WHM/SCH. I had hate most of the fight because, well, my gear and combat skills were a lot better than the other RDM's.
The first time I was dual wielding. We got him down to 40% or so with no problems before a Light Blade slipped through shadows and one-shotted me. The other RDM tried to tank, but Kam'lanaut used the hate reset move and he couldn't get hate off the WHM. The WHM died and the RDM didn't last much longer.
The second time I equipped a shield. I got hit with several Light Blades and survived them all easily (from a high of ~500 damage to one that didn't break Stoneskin). The WHM's MP also held up a bit better overall, but that was also because she used Sublimation the first time, whereas the second time she requested the RDM Refresh her.
Bottom line: Consider a shield in this fight. No matter how good a blink tank you are, he frequently uses moves that strip shadows, and it only takes one unlucky Light Blade to kill you.