When its said, that Naruto has 50% of the powers from the bijuu? He only has 50% from kurama and got only a bit power from each bijuu. So that means, that Madara/Kaguya had more then 50% from the other bijuu(1-8). Or im wrong?
It's impossible to know the exact amounts as most we're never stated, but from what we know what you said seems about right .
Boy are you wrong Naruto has all the Tail Beast powers now not half,not a quarter but a 100%. He free them from Kaguya's body the prophecy has ben fulfilled A Blue Eyed Boy Will Play with them. Stop trying to limit Naruto accept Him as the Master of His Universe.
Naruto has all their powers but not all their chakra....not yet. He will probably get it before the end but he also might not. Naruto isn't obsessed with power so he might let the bijuu go and thus never own/possess all their chakra. Ofcourse, the bijuu would probably willingly help out naruto whenever he needs them but he doesn't officially have all their chakra like madara was trying to do.