Final dungeon/ disc 4 prepreations?

Ok, so i've barely made it through the game this far, if I went to disc 4 now and attemmpted the final boss I'd be killed in 10 seconds flat! I DO want to finish the game (gives me a real sense of achievement :D) and want to see the ending, so, what can I do now to make the final dungeon/final boss less painfull than it has to be? To have even the slightest chance of survival? (what junctions should I have? how much HP should my party have? Weapons for characters? Best limit breaks? etc.) any other helpfull infomation/sidequests would be greatly appreciated !! :)

Gain AP at the cactuar island, you can max out everything in 2 hours there
Have ultima junctioned to squalls attack

warning for the final dungeon, as soon as you enter all your skills are locked, you can unlock them one at a time by killing bosses

Some good general tips:

As posted above, you gain crazy AP at Cactuar Island. 10 AP per cactuar!
The Island Closest to Heaven and The Island Closest to Hell have a lot of awesome invisible draw points. Go there and equip the Enc-None ability to avoid some of the most difficult random encounters in the game if you wanna get some cool magic.
You can get 100 Ultima stones from Ultima Weapon. Refine them into Ultimas!

willing too doubt they have the capability of killing ultima wepaon.

Assuming your pretty low level best bet is too get the best magics you can find stocked at 100 and junctioned too stats.

Fortunatly most of the monsters and bosses go towards your level, so attaining a higher level with characters isn't really needed.

I'd be willing too bet the fight would be easier at level 40 then level 100.

You can still round up stuff and train on disc 4 so you shouldn't hit a dead end but she is a tricky one on your first attempt, trial and error is the best way forward then you'l get a proper sense of achievement :P

Well while you are on Disk 3 it is wise to learn the encounter none ability. With this you can walk the edge of both "ICTH"s and hit the draw points over and over again. Remember in the final battle you can use every character. So it is best to go to Esthar? and buy scrolls that will allow you to junction to HP, Strength, Vitality, Magic, and Spirit. The other stats don't really matter that much. Just make sure you have a GF for each character to junction. When you get full on one magic switch it to another member until they are all full. Another great way to learn spells is to make use of the refine abilities.

I just had my main 3 junctioned normal except for one who I would take off cactuar. Then going into the final battle I would have 2 people who were useless, one with cactuar for kamikaze to do TONS of dmg while killing themselves to bring in someone else, and 3 main people who absorb/immune all elemental dmg, are immune to most status, and hit super hard and fast while taking next to no dmg. If you built your team right you can have mid lv magic junctioned to most of your main stats (str, vit, hp, spi) and use the high lv magic for other stuff (elemental and status absorption, speed if you can junction it on that character). My Squall had max stats with speed so high haste didnt make him faster.