I really like this! I just have to mention one thing though:
- In channel #6 you're alternating the panning between y10 and y9, but because the volume is so low, the difference between them is almost inaudible (you have to turn the volume up in the SPC player and isolate the channel to notice it slightly). Removing all of the definitions and leaving it at y10 (or y9 if you prefer) reduces the insert size by 60 bytes.
It's up to you if you want to update the submission to fix that. It's no big deal though!