Indeed he has to take nature chakra from Hashirama but he has to balance it out himself , and he said it here:
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ural
Wrong, he took Senjutsu chakra from Hashirama, Senjutsu chakra is what happens after you balance natural energy with your own.
Okay , but if he found the amount that Hashi gathered to be disappointing , then he probably can absorb and balance a larger amount , but as you said he have a limit like anybody.
Answered above.
Hashirama split his power among his clones so he wasn't at full power plus he's an Edo so wasn't at full power in the beginning. Don't even say he's edo so his chakra restored, Tobirama already said even if we cancel the clones we still won't make it when they were fighting Juubito so yes clones still split their power evenly among them. Again, that was Senjutsu and not natural energy.
It's not about chakra it's about stamina, Itachi has good chakra reserves but doesn't have the stamina to keep up.
You turn your stamina into chakra. Ebisu explain the process when he told Naruto about how he used too much stamina to make chakra which he used too much or too little. Kakashi further says large stamina makes chakra control harder and blames the fox for Naruto'slack of chakra control.
I mean if Naruto did to him the same thing he did to the Gakido Pain , then Madara can absorb it without turning to stone.
Pain absorbed Naruto's Senjutsu then Naruto began to absorb natural energy which turned Pain to a stone toad. Madara has no training in balancing his chakra with Natural energy, he only took in Senjutsu, 2 different things.
