G'day Titch, I saw yours (coincidentally, about a week after I started playing around with mine), a very impressive job you did on yours. As you say, there's a big contrast between the two and I'm still impressed on how simple you managed to build it. I've done the brick pattern layers previously with a router, (for a telescope) but it's a very time consuming process, and without the CNC, I probably would have opted for a simpler approach for this. I liked your PET bottle idea, I thought it was great! :)
It will be interesting to see what you come up with when you have a crack at the tailpiece :)
Anyway, I just uploaded a video sound sample. There's still a little setting up yet to go, but so far I'm pretty happy with it (Sorry for the dreadful playing!)
https://www.youtube.com/watch?v=apZY_79EMIk