Thanks for taking a look. Just for the record, an emulation of the DEC mouse protocol will be needed before we can give Windows 1 a try.
Back in 2012, i compiled some info here
. I personally never got a graphics card, nor a DEC mouse - so i can't tell which of the serial ports was occupied.
As these mice were usable together with other workstations, working on them might be of some interest to others.