Sasori would need to get through Susanoo. Nothing in his arsenal counters Susanoo. If Madara creates clones of himself and uses Susanoo, then I don't see how Sasori is getting passed that. He would have to guess which one is the real Madara while the others are still attacking him. Even then, if he manages to paralyze Madara, the others won't be paralyzed. Poison Gas is his only choice but if Madara could use Shinra Tensei at a large scale, not only is he going to repel the poison gas but it would also shatter Sasori's body. His heart itself might burst in the process. Poison needles or weapons won't go through Madara's Susanoo or Asura Path if he has it. Sasori doesn't use lightning to increase penetration in his weapons or attacks like Kakashi did or has Susanoo's strength to break Asura's armor.
