The VGA signal outputted by the multiplexer is too weak to drive two monitors. This has required video cables to be manually switched back and forth between the monitor mounted above the laser table and the desktop console.
Today I solved this problem by installing an amplifying (active) VGA splitter on the video output of the multiplexer. One output of the amplifier goes to the desktop monitor and the other to the laser table. We can now monitor the HWS realtime GUIs directly above the optical setup, with no cable swapping.