I have celestial weapons for tidus, yuna, auron and riku, in other words; the easy ones.

For Wakka, Lulu and Kimahri I do have Break damage limit weapons, but I never use Kimahri and Lulu anyway. I have Break Damage limit and Triple overdrive on Wakka's, and I beat all the dark aeons melee. What I'm trying to say is, you don't really need all 4 slots to get yourself an "ultimate weapon". Of course it's cool to have everything as good as it can get, but I always took BDL + 1 other customisation as enough. ^^