After talking about it with the panel on a recent Mac Show appearance (pretty sure this part of the conversation happened during technical difficulties), I pulled out my Griffin PowerMate. The older USB one. While I did upgrade to the Bluetooth version, I still like the USB one better. For various reasons, I’d replaced it with my Shuttle Xpress on my desk, but I found space to comfortably use both and set about re-configuring the actions on it.
This is a companion discussion topic for the original entry at https://brettterpstra.com/2019/07/08/scripting-mac-display-brightness