Final Fantasy X

Try Break Damage Limit, 1 Mp Cost, Triple overdrive and First Strike (or counter-attack). Even though they wont have maximum power because celestial weapons achieve maximum power and if you customize weapons with break damage limit they usually get 60000 rather than 99999 (trust me, I tried)

Celestial weapons are the best, like ROTU13 said if you customize BDL it will take forever to get all the dark matter plus you won't do as much damage as you would with a celestial weapon. You're better off just using the weapons you get instead of customizing your own.

If i were you, i would add abilities like break HP limit, break damage limit, and maybe evade and counter/ magic counter. But i wouldn't customise. As ROTU13 said, the celestial weapons have hidden abilities. These abilities are listed in the secrets FAQ, i believe

The only extra 'homemade' celestial weapon that seems worth it is if you want to be a magic user in battles. For that, make Yuna's "Abraxas"--it has all the properties of Lulu's Onion Knight--Break Damage Limit, One MP cost, Triple Overdrive (or + Mag power %), Magic Booster. This is just because I hate Jumbo Flan. If you have the FFX Intl I'd save your Dark Matters for armor.

Also confirmed--60,000 or less dam with str 255 on Juggernaut, Nemesis. Part of the problem I believe is that many monster arena (and probably Dark Aeons) fiends are immune to armor break (frag grenade included).

Celestial weapons ignore defense!!! Believe me, it's best weapon for hard boss like dark aeons, nemesis, penance. I've tried it myself

I wouldn't waste customizing weapons unless it's Yuna's as said above, save the items for armor. The celestial weapons have power bonuses, like Tidus and Wakka hit higher at full health and Auron hits higher when near death.

The reason why Customized weapons only do around 60k is because the Celestials ignore Defense.

I reccomend getting a fully open slotted weapon from Wantz, and adding Break Damage limit, triple overdrive, evade and counter, and gillionare or one mp cost, depending on the character. Each one of the ones for these abilities, except for evade and counter, can be obtained by unlocking monster arena bosses

If u customize a weapon u just hit for 60000,trust me no matter what skill u choose,becuase celestial weapon have secret abilities like ignore defence so don't waste your time

I wasn't aware that you could customize the celestial weapons. Once you upgrade them to their max, (With both Crest and Sigil) there's no more room for improvement.

Why use the characters use the aeons...that what i did....

The only way to make better weapons than the celestials is to use FFXED. For instance, you could make a sword that always hits for 99,999 regardless of your Strength or the enemy's Defense.

Break Damage Limit, First Strike, Piercing and Counter-Attack is pretty useful.

The answer to your question is no you can not customize the Celestial Weapons and for you to hit for 99,999 HP you have to be at full HP and have at least 210 ATK.

the Celestial weps cannot be customised true but then again u wouldnt really want 2 because some items are hard 2 get if u dont know how 2 get them (but if u read FAQs on here ul get all items u need in no time) but they also have Hidden Factors like icantfindname said like how aurons wepon is more powerful at low health, but a custimized wepon wont have this, and more hidden factors. all of the Celestial weps have them u just need 2 figure them out but Catastrophy said u need 210Atk 2 break 99,999 HP im not sure it does go past it but if u want 2 try it i suggest u use Break HP Limit and get the Sphere GRID completes along with adding the additionl HP ones 2 it but Rikku has a certian Mix cant remember exacly what it is but the Single item does Double The Characters Max HP for that fight say ur standard max is 4,000 u will get 8,000 but with Break HP limit and u have 40,000 ul get 80,000 and so on it might get u 2 break the 99,999 with Break HP Limit even tho its 99,999 i thinks max (i also know Cheat Disks make it go 2 2billion HP)

so main part is Celestial Weps cant be custod but have the best benefits in game or u can try mimic it and not get the hidden factors that can be great helps 2 certian people