Your evaluation of your various recorders is very interesting. I hope I get to know mine as well as that!
When I got the box treble, the Kung became my back up. I think it was during intense pre-exam practice that it came out to play, and I realised I could hear the difference – I was extremely amazed to notice, even more so when I demonstrated to my teacher and he agreed that there was a difference and I was right that the Kung suited the piece better (a movement from Gordon Jacob’s Suite, but I can’t remember which one!)