There are certainly influencers that I am using while developing this idea. Here are links to their videos, libraries, and project pages.
From the Internet:
He is loud and British, but you have to admire his enthusiasm!
OzBot - Red
These are nice robot builds. and good inspiration and guidance.
Of course - this guy's proto-robot army. From his 2018 blog: Electronics and Robotics.
Open Source Libraries:
I am benefiting from some OpenSource libraries
Jeff Rowberg’s I2CDev
Brett Beauregard’s PID Library
More General Inspiration and help:
Homofaciens project page on using Transmissive optical sensors to create DIY servos.
This looks pretty detailed too.. kas on the Arduino Forums has a nice long thread on the topic of Balancing Robots. I certainly liked his disclaimer:
"I invented nothing
I read A LOT and went by trial and error"