I tried equipping Cloud with all my Counter materias and Magic Counter + Osmose earlier, to try and keep MP high, but they force me to heal up every turn or die. I'll try it with Restore and see if I can sustain that way, and do some damage. Hope that Hidden+Elemental works great too.
Great to hear Jenova doesn't do % damage, but what a pain in the ass she is. Physical and magic damage and statuses which you can't afford to affect you. Ribbon is nice but, lowers my defense being unable to equip Protect or Touph Ring. Not sure if those are worth it anyway as their attacks seemed to ignore Wall and Touph Ring halves restorations. But with Ribbon I can't buff myself, Haste would be so useful as Cloud is a bit slow. Could try it without Ribbon, buff up, and hope she doesn't status me before I can use Resist.
EDIT: Ok it was really easy with that setup; Hidden+elemental on armor, Magic Counter+Restore and Planet+MP Turbo, MP Plus, then fill the remaining slots with Stat boosting materias (Covers for Vit, no need to worry about Magic Defense as hidden element heals you) Then just spam Pearl on Jenova and chug ethers and elixirs when low MP. I was thinking there has to be some trick to this fight. Couldn't figure out that Hidden element is a thing, none of my materias even had the hidden element displayed but Comet works, even though it says non-elemental.