It would be a hard match for jiraiya but with gamabunta and sage mode he has all the tool for win that fight.
hiruko isn't be a big problem ,a rasengan is enough .
sasori's attack like these one can be dodge with a good speed or a good defense.
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chiyo had a shield of chakra,jiraiya has also Needle Jizō that is endowed with a capacity to injure and kill on par with that of metallic weapons.
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about satetsu ,
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sakura didn't got much damage apart 2-3 scratch and she didn't have any shield. ,yes it's enough to get affected by the poision but Needle Jizō can again permit jiraiya to not got a scratch. that defensive technique is very usefull against sasori.
whatever jiraiya would need time to enter in sage mode to for his security in addition of Needle Jizō and he will mostly need to attack .
To enter in sagemode jiraiya can use his sound genjutsu but some people thinks that sasori isn't affect so so it's not 100% sure that it works or not.an other way to find the time needed to enter in sage mode (diversion,clones,hidding in frog's stomach...)
SM will permit to increase his speed and strengh.he'd have obviousely no problem with his incredible speed and strengh to take the 3rd kazekage puppet down with a punch like sakura.
now sasori show his real apparence .
his long range weapon atack like on that page won't works against a jiraiya at full power ,he'll dodge it easily .
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jiraiya's physical strengh in sage mode won't help to kill sasori since sasori can reform his body
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once sasori summon his puppet army,jjiraiya would summon gamabunta and go on top of him.He can erase the field of these puppets with his his Katon: Gamayu Endan that use gamabunta's oil in sage mode ,it's a big scale jutsu enough to erase the puppets .
note : sage mode increase ninjutsu's strengh ,last time he used it was not in sage mode .
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Senpō: Goemon can also be usefull for puppets
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the harder part for jiraiya is to find sasori's secret ,like against pein ...
he has ma and paa near him so i think that they'll see this "sceal circle" on sasori's core .
if sasori's transfert his core by using his chakra ,jiraiya in sage mode would not have problem to sense his chakra ,so a surpise attack from sasori is impossible like when he did to sakura.
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jiraiya can kill sasori by using Chōōdama Rasengan that is said enough powerfullit would easily hollow out an entire mountain.
Ive already argued everything you have said and even gave jiraiya sm from the start. If you look at the location, a big summoning cannot be used, not to forget iron sand can shield sasori.
You say a rasengan alone would take care of scorpion for, you serious?. That form alone is very difficult. It would be wise not to try a close range fight with it due to its many traps