We didn't have to wait long as we received this email from Rafi :-
I want to thank you for the Video Conference plugin which I used in a community video sing-along from home.
I’m in Israel, today is our Independence Day and the clip is a Hebrew song, but the image speaks for itself 😉.
I received 58 clips from home-made videos. I mostly used 4x4 and 9x9 to show people in larger clips, but towards the end I put everyone back in 16x16 and then combined 4 16x16 to show all 58 clips simultaneously. I didn’t create compound clips as you showed because that would still require processing all the clips at the same time (and my Mac is getting old). So I exported each 16x16 set as a ProRes movie which I then re-imported and put all in a 4x4 as you suggested.
So thanks again!
Here's the result, there is a 'wow' moment at around 3:30
Thank you to Rafi for sending this in, it really made our day.