Issues with Wifi / bandwidth / SUPPORT required

I recently tried to use CoSpaces with 16 Oculus Go headsets in class. The students created their assignment and were then supposed to look at the spaces in VR. However, some of them weren’t able to load a space at all, some only saw part of their space in a round field and one or two were able to really be in VR. Also, most of them didn’t see the arrows to switch to another scene. This was quite frustrating.
I don’t think the Wifi was so weak, the bandwidth should be okay because this is a school in a big city and they use it with iPads without any problems. Moreover the class was over lunchbreak, so we were the only ones using PCs and headsets.
Is there a way to find out how much data has to be loaded?
Using headsets in class would require me to be able to reload spaces - but maybe not the whole space but just changes?
I also want to present a rather big space to parents in about a month. I will have the 16 Go but I am afraid, the spaces won’t work and it will be a fiasco. People (parents, colleagues) are already sceptical about the projects I have students do, so that wouldn’t be beneficial.
Before the Oculus Go app was published, it was possible to preload a space entirely and it wouldn’t need the Wifi connection after that. However, this is not possible on the Go anymore, right? Otherwise I would be able to preload the spaces …