So I've come up with a rough estimate of minato namikaze's chakra level's I don't know how much chakra is used to perform the ftg technique or some of his other jutsu so I'm going to make it as close as I can and feel free to object vote or comment

During minato's fight with obito and kurama he used the following

-Flighing thunder god 13 times and using alot of chakra to keep kurama in place during kushina's pregnancy wich totals up to at least 1 rasenchurican worth of chakra

-then the s/t barrier he used to stop the tbb and not only stop it but redirect it is about 2 rasenchurican

-then when he teleported kurama and a fully powered bijjudama should be 5 rasenchurican worth of chakra mainly because before he used ftg on kurama and the bijjudama he said he has to use an equal amount of chakra to be able to send it away and the mini bijjudama four tails used on oro is about two times stronger than the rasenchurican and the bijjudama minato teleported was bigger so I'm guessing its twice as strong and would take 4 rasenchurican and to teleport kurama's body with ftg is also very hard and he used a contract seal on obito

-and then he performed the eight trigram seal jutsu three different times one on him one on naruto and then readed it on naruto and seeing how that's one of the strongest sealing jutsu and held kurama for multiple years I say that each seal is probably 3 rasenchurican
And he stored extra chakra in naruto and summend gamabunta and summend gamatora

I think it ads up to about 16 rasenchurican worth
feel free to make your own Charts and comment a poll will be up momentarily