Zach,

Since I'm new to coding in C++, I've spent some time "re-coding" the
existing firmware to help me understand how the language works.

In doing so I built up the ability to handle microtones in the way I
envision. I am working on getting a GIT up for the code but in the
meanwhile please take a look here:

https://create.arduino.cc/editor/_/ec86eb07-3303-4c02-98ee-786f9e3bc498/preview

Will send some detailed notes later.

To get exact microtones I had to modify the following in Arduino IDE:

Go to definition for the tone() function
Should go to:
Tone.cpp, line 58 =
void tone(uint8_t pin, unsigned int frequency, unsigned long duration) {

Change it to =
void tone(uint8_t pin, float frequency, unsigned long duration) {

If anything else needs to be changed to "float" at compile then do
that too. I couldn't figure out where to do that in a patch though.