Thanks for your patience while waiting for my response, I wanted to double check the information before telling you specific numbers. In terms of project 2.1, the likely maximum number is approximately 15 users, but more likely to be around 5 users at a time. Allowing for more flexibility in your design for different numbers up to 15 users (or even more if possible!) would enable others to join the virtual experience and the elders to share knowledge and is encouraged. However, you can assume 15 people would be the maximum at any time.
I hope this helps!