Hey! Although I have a liiittle experience at using English UTAU voicebanks I made and tuned an original with one, but I' m pretty bad at phonemes orz I wanna comment ^^; though forgive me if my critique is messy.
Honestly, at first listen I really liked how you made her sound soft in the first part. I found it pleasing to the ears! The one time I used Teto English, I thought she sounded harsh - I abandoned that cover. orz However, that's not the case with this snippet. Her tone sounds nice here. I love that "before I make a move~~~"
However, the next thing I noticed was that I didn't really understand the lyrics. This isn't entirely your fault, however; I found Teto generally found to understand in English. also real humans can be hard to understand too at times//shot But if you can find ways to work on that, great!
I do like the tuning, the portamento was good, it was subtle so not too exaggerated but also not robotically flat. I can't really think of much points of improvement of that front.
Mixing notes... The reverb sounded nice, but I think maybe it could be turned down by just a bit. I'm not so sure though... You might also want to lower the volume of the vocals by a really tiny bit and increasing the volume of the instrumental by around the same around to make them sound more balanced, but not to the point where the vocal is drowned out. I'm not sure if it's just my headphones or if the vocal sounds a bit too loud. Just my opinion though, you might want to play around with it a bit. Also, did you apply mastering to the whole thing or not yet? I'm not so good at mastering myself ^^; but if you're using a DAW where you can apply effects to the master track, maybe applying a subtle compressor would help the dynamics between the vocals and the instrumental?
It's actually a pretty good attempt imho, my covers sound worse orz good job and I hope I made sense!
