Sasuke isn't a Jinjuuriki or anything. He has no another chakra sources which he activates. That chakra Hagoromo gave him became a part of his core chakra. That much of chakra and on top of that ability to sense Natural energy is all what it is necessary to be SM user. I don't know why I'm keep bothering with narrow minded people like you.
I know all of that, but still he received a massive power up. What I want is a proof that before this powerup, he had huge reserve, something people said.
Because without this plot asspulled powerup, he would never be able to be a sennin, even a nobody who received such powers will be monstruous. Even now I don't think he has the goods for it like stamina. Even if the chakra is linked to it, it takes a very strong body and an absurd amount of guts to be a senin, and guts, sasuke didn't shown much. (Or you play like kabuto with the snakes.) Jiraiya had very, very large chakra reserve and had a very strong body just by looking at his stature, moreover he was the guts type of ninja. The only thing that's not logic to SM is Minato, but unlike the explanation is that he had the strings but not the body for it, it's an error.
This powerup make irrevelant nearly all the messages of the author and ****ed up the characters logic:
Hard work/training is needed to become stronger. Nope if you are legendary transmigrants. You can be a god if the grandpa comes to see you.
With hard work a no-name can equal a big name genius: Naruto who was a no-name apart of being the Kyubi holder is finally the son of the "great" yondaime and the previous kyubi holder who had a special chakra against Bijuu. Moreover he is the transmigrant of one son the of sage of 6 paths and he is the prophecy kid who will bring peace. What a background for a no-name type of character in part 1.
The next generation always surpass the previous: hashirama/madara part 2 power scale nullifies this. ( Although shodai 1st part was the best: very strong but dealable)
While naruto is a stamina freak who wins through endurance and guts his fights, sasuke was the opposite: designed for the most time as someone deadly strong in short fights, but not very good with long ones. ( that's why nearly all his fights are short)
The powerups ****ed up completly this equilibrium.
Moreover after re-reading, and comparing, sasuke 6 CT were a lot smaller than the one pulled by nagato.( the one nagato made is 2 or 3 times bigger) Moreover, nagato had to deal with 6 body control + pull a massive ST + make a full combat with regenerating bodies.
Sasuke without hagoromo chakra would never be able to do that.
That's why this crap for both naruto and sasuke don't count as legitimate powerups but as "deus ex machina" crap in order for them to have the weapons to deal with what they had in front of them, screwing all the epicness potential.