The dark aeons are stupidly strong and appear at the most inconvenient times. Im not looking for a "way" of killing them because i have destroyed 2 of them with Yojimbo and it took the fun out of enemies with 99,999 attacks (if there is any).

Most people say have stats at 255 and health over 40k, im stumped, im more into Final fantasy 7 & 8, so does anyone know any good places or tactics to get this mega stats?
Anyway:
My strategy is to get a fully-charged Celestial Weapon for everyone.

Then I go to Omega Ruins and bash some monster until my Wakka and Tidus can do about 50000 damage respectively.

Ultima Buster can drop a weapon with this three ability but he have massive amount of HP, you really need to maximize your party stat before it.
He can't get them all if there are Dark Aeons. He'll have to do with the ones he has, or Yojimbo his way through. Although if he REALLY wanted to have fun with these games, why get the Int version? Yojimbo w/ small Zanmato costs + Ribbon = FDQ of zero. Be a man and take your spoonful of confusion/berserk/poison. I don't care if you don't live in North America. Those people are also lying to you. You only need stats at 150 in all areas except Luck. HP is a non-factor unless your stats exceed 255 in all areas except Luck.

By the time Tidus and Wakka do 50,000, if he unlocks Nemesis, they will be seriously underleveled. Also, don't bother with Luck until you have completed the Sphere Grid for at least three characters. It's simply not useful enough by the time you have 255 in all stats.

5 million HP, Ultima Buster has, to be exact. Also, many other monsters in the Arena drop this type of Weapon configuration.

And also, you only receive AP if you win the battle, not if you run/Flee. Do NOT attempt to Customize the Triple AP onto a Weapon. It is a waste of your Wings to Discovery. They could be better used to customize BHPL, particularly considering how difficult they are to obtain at this point (*cough* Shinryu *cough*)