Hi Javier,
[I have replied you through email earlier, but just because other people might have the same question, so I'm replying you here again:)]
Thanks for choosing SKYBOX for your video streaming :)
The change in the amount of devices connected via AirScreen affects mostly the bandwidth. 5 devices should be okay for standard and stable 5G wifi networks, especially if video size is not significant.
As for the configuration of your PC, I'm not certain of the lowest configuration required for SKYBOX desktop, but I think my PC currently is doing it smoothly and it's not a crazy configuration, just a standard gaming PC, so it might just give you some idea about the requirements: CPU: i7-7700HQ @ 2.8GHz, RAM: 16.0 GB, 64 Bits, GPU: Intel HD 630 (integrated) paired with Nvidia GTX 1060 with 6GB GDDR5 RAM.
Anyways, if you are not familiar with PC configurations, I suggest you just test them out with one device connected, it should be the same with multiple devices when it comes to PC configuration.
If you are experiencing lagging on your PC, try not to open the preview mode(if you were in this mode of course) , because that takes up extra CPU as well.
Good luck with your project,
Andy