If you can afford to use Flint Caviar in t13 then I think you can cap it at 16 ACC. If not and want to use Risotto I believe it's 32. You should sacrifice the crit to do this. There is a way to reach it the cap w/o putting acc on your weapon and still be a viable build but it requires Dreadwyrm pants which ironically drop from the turn you're trying to reach cap for. This is all IIRC. I'm no Ninja expert. There is a thread called Ninja Superthread that has a lot more/better info than I would ever be able to provide.