Would he have enough to be able to defend against the offenses of IS?
I'm gonna do a bit of comparison, feel free to bold what you think is incorrect (but just indulge this thought

).
Madara's susanoo magatamas were able to penetrate gaara's sand in the scan below, it took onoki's rock golem as an added defense in order to stop it. Now what this means is that gaara with desert level sand can't defend against madara's magatamas.
Now the question here is, how do I compare madara's magatamas with sasori's IS? Well its pretty simple, the
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of the magatama's is arguably weaker than the
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of the IS. Now this is important because sasori's IS is thinner & therefore would logically cause a smaller impact radius than madara's magatamas, however this shows that sasori's IS is much faster than the magatamas.
Therefore sasori's IS is not only better at penetrating the defenses (because of its aerodynamic shape), but it is also much faster, going by the scans of both jutsus being thrown. If madara's slower & oddly shaped projectiles can easily get through gaara's desert level sand (btw here is the
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of a magatama on tsunade for comparison), then I see no reason why sasori's satetsu can't do the same with gaara's gourd level of sand. Desert level sand is arguably different as he could make much larger sand sources.
Tell me what you think