First off, you used Bibi Jyougasaki, so your taste in voicebanks is already 100%
And with your tuning alone I think she sounds pretty okay. There wasn't really anything that stood out to me as sounding bad or off key etc. Honestly I think the tuning is pretty solid, but you'll just have to decide if it's good enough for your standards.
One thing I like to do is find like an Utaite cover of the song I'm tuning and take some ideas from the cover to try and imitate it in my tuning. I think it's also a good way to learn how real people sing so that you can try and learn how to make a voicebank sound more natural and human like (since that's usually the goal with most tuning). but it all honesty, a lot of my tuning is pure guesswork LOL ;;