doesnt sephiroth have 1,000,000 health or something like that when you fight him at level 99? i remember my cousin beating sephiroth with everyone at level 99 and having to use KoTR for over 10 minutes before sephiroth died. im quite sure that the movers (red dots that give you more EXP than the pots. WTH. that rhymed too.) only appear in one part of the northern cave. just go down until you encounter some movers and then train in that spot for a while until you have the stats you want. im on level eighty-something and i have everyone on 9999HP (with help from HP plus materia.) so you wont need to level up loads to get high HP. just make sure when you use HP plus materia that you use mstered ones or else the less useful 10% + HP materia will take up a lot of space and make you vulnerable to the aire tam storm attack from emerald weapon.