If I am not mistaken, cannon Minato's fuinjutsu skills were at least Master Level. He was able to to perform the 8 triagram seal in a few minutes and was able to use Reaper Death Seal.
Hey author, why dont you try exploring Lucy(2014 film). She was able to manipulate time to the beginning of the human species it self. She could even merge with the universe and become nigh-omniscient.