Here are my thoughts for what's it's worth.
I turned on all 4 machines I have and posted the stickers above. I opened the panel and at the source read 3.7 amps on a fluke meter.
I have no way to test all the machines or even one at this point because I have no one else to play them while I run the meter. I will do this when I have a chance out of curiosity.
I use an 1800w max sure proctector/power Conditioner on the circuit and have had all games running at once without tripping the breaker (20 amp) .
Something to consider is also the type of breakers/wiring you have in your house. Newer breakers are alot more sensitive and likely to trip than older ones. Some never tip at all! Espically if your house is built on a newer code with arc fault and gfi breakers (which I'm not using to supply power to my games) .
Just some things to consider. In a new build I would rather have too many circuits then not enough. Being an electrician I over engineer and over think all electrical in my house/shop.