We wrote this program quickly back in 2018 by modifying the Balancer example program from the Balboa 32U4 Arduino library available on github. Keep in mind it is not as polished as our usual published examples, so in general, the comments are not all updated for the line following purpose, and will probably take some work to optimize for your robot’s combination of gearmotors, gear ratios, and wheels.
Additionally, the Balance.cpp and .h files are a little different from the ones on github. We took a look and suspect the differences will be inconsequential, but it might be worth looking at and testing yourself too.