My first half-assed attempt didn't work so well. I'll try again, but I've also gathered more 60 Hz references (one of which immediately revealed an error in my envelope period handling).
In addition, I used your YM2FYM tool to convert this very familiar track I spent a lot of time listening to coming out of a '13, so thanks for that.
https://www.youtube.com/watch?v=-ADL_PIENgs
I'm sure it will see a lot more use.