Installed the second MRC Control Master 20, giving the layout full block control. The installation was pre-wired some time ago and passed the functionality test on the first try, thankfully since I don’t enjoy troubleshooting wiring!
My temporary jack mounts for the walkaround controllers were a little bit too temporary, demonstrated by one of them parting company with the layout. I reinstalled them with slightly heavier components. Eventually, they will be installed into the masonite facia. All in good time.