See I never understood this. People automatically place Naruto above Jiraiya without really thinking about it, they just go mostly by manga portrayal and base it off the fact that Naruto "won" against the Pains whereas Jiraiya lost badly...and the fact that Naruto surpassed Jiraiya in his senjutsu training and became a "perfect Sage" while Jiraiya is still "imperfect".
Naturally we are going to go by portrayal...but feats are also in his favor. Pain Arc Naruto was stated and portrayed to be above Jiraiya, War Arc SM Naruto is a tier above Pain Arc SM Naruto.
But if we take a closer look at things, is Naruto really that much stronger than Jiraiya? For one, Naruto can remain in Sage Mode only 5 minutes at a time, and can only prepare two shadow clones to gather nature energy at a time (which in itself, has its downsides: the clones need to stay completely still to gather nature energy on the battlefield and Naruto has to guard and protect these clones from his opponent so they aren't simply killed making his efforts wasted.) Whereas Jiraiya with Fukusaku and Shima on his shoulders has unlimited Sage Mode, chakra permitting of course.
OP said that he wants to test their full abilities, so Naruto gets copies of the Toads. Thus he can enter and stay in Sage Mode indefinitely. Besides, even without them, Naruto's limit is clearly no longer five minutes.
-He did training to extend it.
-Used Sage Mode from the time he attacked Madara to after he was revived, and that was much longer than a mere 5 minutes. Not to mention he used a giant FRS, so 3 FRS aren't his limit anymore either, meaning he has more Sage Chakra available to him. He can also enter Sage Mode in a few seconds, so the clones aren't necessary.
What's more, is that all toads of Myobokuzan respect Jiraiya and are more loyal to him than Naruto, for obvious reasons, like the fact that Jiraiya has a much closer relationship with them all. Should Naruto summon any toads to do battle against Jiraiya, they would instantly betray him and side with the one they know better (Jiraiya). This makes a huge difference in the battle, since all toads (boss toads, Barrier toads, Sage toads, even the toad which holds the key to the Kyubi) are on Jiraiya's side.
OP gave Naruto clones of the Toads.
Jiraiya also has two teammates (Fukusaku and Shima) to help him analyze the battle, strategize, and perform powerful combo attacks with him, as well as act as his support. Two heads is better than one, so three heads are clearly superior. You might disregard Fukusaku and Shima for the most part they actually have very powerful and versatile abilities, which are increased even more when performing combo attacks with Jiraiya or each other. They have Frog Song, Toad Confrontation Chant, Goemon, sensing, both are equipped with tongues to grapple their opponents (Fukusaku's can be sharpened to cut through solid steel and Shima's can poison opponents), either can summon 4 boss toads on their own so Jiraiya can preserve his chakra, they just add so much more to the battle.
Frog Song would paralyze Naruto, but then again many clones let Naruto not get caught by the technique, since Jiraiya won't know which one is the original and which one isn't. Their elemental Ninjutsu get evaded, Gama Rinsho isn't happening here, not when Jiraiya isn't going to last that long, and summoning 4 Boss Toads is useless when Pain Arc Naruto already fodderized boss toad level summons. Pain's summons.
And Naruto's sensing>>Jiraiya and his Toad's sensing.
But once again, read OP. They each get their own set of toads.
Then you factor in Jiraiya's versatility. He has a huge arsenal of jutsu in all shapes and forms which can be used for many different various purposes, but what can Naruto do? Shadow clones (which Jiraiya can do), rasengan (which Jiraiya can do), summong toads (which will immediately side with Jiraiya), and Rasenshuriken. That's pretty much it.
Except Naruto does everything he does better than Jiraiya.
-Better at clones.
-Far better at the Rasengan.
-FRS
Then there's this whole "perfect Sage vs imperfect Sage" stuff...well we already know that Jiraiya has an advantage in that he can remain in SM much longer than Naruto. The main difference is that Jiraiya obtains some toadlike characteristics, which will make him unpopular with the ladies but oh well. His sensing isn't as good as Naruto's, but this can be compensated for the fact that he has two sensors on his shoulders with over 800 years of experience each, in addition to a sensing barrier. His taijutsu isn't as good either, but that's only a factor if Naruto can close the gap between them very quickly.
Naruto>Jiraiya in strength, speed and reflexes going by feats, most likely durability too since Perfect Sages should get a better boost, and they do, which is why Naruto's physical abilities are so much better than Jiraiya's by feats even though they aren't in Base.
Even with the Toad Sage's Sensing and his barrier, Naruto's sensing is still vastly superior as it acts just like Sharingan, precognition, but in the form of sensing.
Naruto is faster than Jiraiya, has better reflexes, and has clones to propel himself. There is no way that he isn't closing the gap, and once that happens, Jiraiya gets dominated by Frog Katas and superior strength and reflexes. Along with some Rasengan variants for good measure.
Under the OP's conditions Naruto obviously wins. Under normal conditions in which they both start in base form, I would give it to Jiraiya mid difficulty. If the conditions are normal but they both start in Sage Mode, I would give it to Jiraiya high difficulty.
If they both start in Base w/ no restrictions besides the fact that Naruto can't go above Sage Mode, he stomps Jiraiya. Jiraiya takes a while to summon the Toad Sages, Naruto enters Sage Mode in a matter of seconds. He enters it, attacks Jiraiya and slaughters him.
If they both start in Sage Mode, War Arc Naruto still destroys him due to being superior in pretty much everything except for irrelevant stuff like versatility.
