There's no sure way to beat exam 70 unless u're at 14k+ power or something.

I can only help fire mains because the sleep will render jiraiya's jutsu mystery alongside the fact he won't attack when he gets sleeped,even if he wakes up afterwards.

There's no lineup since gamabunta will always just kill someone with 1 atk and he can't get comboed, so forget about using ninjas that work together.

Some ninjas that can be used are 3*naruto,Tobi,GNW Kiba,Lee,Asuma and Neji. I personally managed to beat it without using any clones if it gives u any hope.

U want to use chameleon as ur summoning alongside phoneix fire chase and oboro clone with enchantment of fire style (every bit helps, i once got him to 20 hp and died).

Don't get me wrong, u'll still need a lot of luck to win, but this is all the info that can help u rly, nothing else that can be done except hope he doesn't 1 shoot u.