Ok Im tryin to grasp the Magatama thing and I know theres a help post on this already but its not givin me the info I actually need. Ok I have 2 Colored Carp Magatama which has 25% Affinity Catfish Magatama which has 22% Affinity and Dusk Magatama which has skill force at 47% now my question is these empty slots what exactly can I place in there that will actually benefit my Oodachi build? and do all these Affinity stacks actually help me or limit me. TY for anyone that replies.

I can't really answer on the specific maga you need, just look for skill force is the best I can give you.
As for affinity, it will eventually limit you as there is a 3000 weapon affinity cap as of the current content cap in which after you reach the cap, affinity will help you no more in terms of dmg and you should instead be relying on skill force to increase dmg even if it means replacing some of the affinity magas.

TY good sir