It's hard to say really... I would give it to EMS Madara very high difficulty.
Yes.
You do know that he can control the Kyuubi, right?
I thought so, then my original post still stands. Speaking of, seems I don't need to demonstrate my point earlier that people won't get the difference between Edo and non-Edo versions of Madara xd half of the posts so far did it for me.
How so?
Well mainly because of perfect Susanoo, it is as big as a mountain so i believe it can tank Flash Bijuudama, while it's attacks are devastating and he can easily spam them.
I don't believe Madara controlling the Kyuubi is a factor here, Naruto and Kyuubi work in unity now they can snap each other out of genjutsu and their chakras are now molded/combined it's one thing to control just Kurama and his chakra alone but it's another thing to control 2 different charkas bound together.
ems madara>naruto
both can change the landscape but madara can get them off more effectively than naruto. perfect susanos normal means of attacking rewrites maps but naruto can only do this with tbb which needs to be charged. perfect susano can easily strike in the time it takes naruto to charge a tbb. also perfect susanos durability has not been tested so its unknown whether it could tank tbb.
Ems madara handles bm naruto easily. He can easily supress kurama,his perfect susanoo can swing a blade much fasyer than a tbb can be made,unless bm naruto has the durability of multiple mountains,he is finished, dust release didnt scratch ps,a tbb will be sliced in half by those swords or just be tanked ny the susanoo bm naruto can't touch ems madara.
Naruto is overestimated. Did Naruto use his bunch of clones against Nagato? Did he use them against Tobi at the beginning? When did he used them in an actual fight? The clones would just drain his Chakra. And one swing of Susanoos sword would destroy them. By using his perfect tailed beast bomb, he is a perfect target for Amaterasu while forming it in his huge Chakra cloak. And if Tobi could simply dodge Narutos mini Bijudama, why not Madara? You don't have to overestimate Naruto so much.
It's not tanking a full TBB explosion from a fresh Naruto (current Naruto been fighting for days).
No, just no. Madara low diff.
We don't know how powerful Narutos Flash Bijuudama would be if he was fresh, we don't know if it could increase in power at all, it's just speculation.