At Mountnessing we usually display the scrolling results on the laptop from the end of round 2. We don't enable the rankings on the scoring devices until the start of the penultimate round, on the grounds that it would slow down the movement and we usually struggle to keep the session running to time. this is all a hugely debatable issue, e.g., does it affect players' tactics, etc? If you took any 4 Bridge players you would probably get 5 different opinions as to the rights and wrongs. The important thing is that the system provides you with the options to do whatever your club policy dictates. Some (wealthy) clubs with their own dedicated premises have 'big screens' that they might use for training / teaching as well as for results displays. I don't think it takes 'rocket science' to connect a normal laptop to such a screen, though I have never personally done so.
Alaric