@Nurgelrot thanks. for the feedback. Actually what @dc42 is saying is right. When the screen is dimmed communication with the printer just works as normal and PD should receive all updates.
So if you still observe weird things don't hesitate to start a new thread describing your problem.
@mfs12 We are using it regularly, and it's working very well. But we can't compare against the previous methods as we only recently decided to release our own version of the firmware (we'll keep it in parity with the official releases) that contains several tweaks unique to our printers. Our only issues were with the setup of the environment which were documented earlier in this thread.
Thanks. I see pins that have the same labels now too, not sure how I missed that previously.
I decided to desolder the four-wire anyway to get more space for structure, so having done that I decided I may as well direct connect the wires. Seems OK.