Very nice, and welcome to UU!
To answer your question I'd say the UBASS is a little hot in the mix in the quieter parts especially the intro. The other "issue" (I play bass and have a UBASS, BTW) is that for this arrangement there are a couple of places in the piece that just cry for the bass to ring a nice long, slow decaying sustained note and that's pretty much impossible with a UBASS no matter how much compression you run it through. Through the fast "center" of the song the UBASS works quite well though.
If I were in your shoes I'd probably use one of my full-size steel-string basses for this particular piece or I would sit out entirely during the intro and come in once the guitar goes into the "driving" part.
Overall though, it was very nice.
John