Thanks for this thread! The info here was very useful.
Sooo, I sent all 17,576 three letter combinations to the MX-100 and think I found all of the usable commands, plus a few mysteries.
Also I made my own smart (2 way communication) on screen menu to utilize them. It makes learning what the settings do, experimenting, changing settings and just plain checking how you have things currently set a pleasure.
I tried to match the Mcintosh aesthetic (black background, bright green font, big blue rectangle to select items) and made my own font just to have the Mac logo. I love how it turned out! I kept adding more features I wanted and still have a few things I want to do, but itâs 98% there and I donât see myself jumping back into it to address anything else unless I learn more python or find a bug.
I added lots of features like presets, favorites, turn on volume, amp 2 off in stereo mode, meter light control, a âquick viewâ pop-up to check all your current settings, etc.
I also solved the âDynamic EQ/Volume boosts surround channelsâ problem that exists in many Audyssey products. Very proud of that part and it forced me to learn some Python too. You can enable or disable my fix.
It requires eventghost fyi. If anyone wants to try it out or wants more detailed info, lmk. It was a big undertaking but fun and Iâm very happy with it. Initial setup will be non trivial. I could use a hand if anyone has experience with Python (like adding variables!) or EG plugins. I only know what Iâve taught myself in the course of this project but I want to make a few tweaks first if I were to share it.
Even if no one wants to use it, I really just signed up to say thanks to everyone for sharing the info in this thread 
It only let me put one picture but hopefully you can see it and get an idea