Double rinnegan sasky?! You mean sasky's fantic full power is double kamui with kakashi's ps??? XD
No, the true power of the eyes is when you have both. Madara only had one of his Rinnegans so he wouldn't be able to use every jutsu that we know his Rinnegan has. The Rinnegan Obito had contain the power to pull souls (he wanted to pull Yamato's soul out), control 6 paths, and revive so the eye Madara had wouldn't be capable of this. Obito couldn't awakened Susanoo without having both eyes.
But Sasuke Rinnegan is different from normal Rinnegan.
What thought do you have regarding this matter?
Hashi still have a little bit of Ashura chakra
If not how he can summon Hagoromo when touching Madara lower half
Read Hago statement in chapter 686
Being different doesn't mean it's stronger, it's still was made with half the power, Sasuke have Yin chakra of Indra and the Sage gave him Yin power while Madara got his Rinnegan with both yin and Yang chakra of Indra and Ashura. The Sage told Naruto that Madara got Hashirama's DNA before the Transmigration was over and that's how he got his Rinnegan
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. Naruto is the one Sasuke need the DNA of to get the Rinnegan like Madara did not Hashirama.
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