Destroy Sunni Caliphate as Sunni Sultan - Strategies

[Gnome Boy]

I am playing as custom sunni ruler (Sultan Sultan of the Sultan Sultanate) in Iberia and want to become caliph. My dynasty is sayyid, so I've got this covered. But to create the caliphat myself, I have to destroy the existing caliphate somehow, which is still held by the Abbasids who are far away. However they are in diplomatic range!
Now my plan would have been to marry as many fertil women as possible to their unlanded sons to make as many dynasty members at possible to make them decadent. Then after a decadence revolt the caliphat should get destroyed and I could create it.
It is my first muslim game, so I don't know if this would work. Have you some better or faster strategies for me?

[Cheese]

It won't be that easy. The caliphate doesn't get destroyed in a decadence revolt. It would be easier for you to get a claim on the caliphate and then win it in a war.