I guess the biggest gathering we had was like 45 odd people way back in 2014 anniversary meet as below. As far as I remember for any regular meet the head count is usually <=20!
So these days 20-30 would be max I guess. But I guess you know more so you can suggest.
Normal is 25-30 on Sunday who reach without any notice !
They Gate Crash !
Many are not willing to attend any meet for now.
Later when their children will start to goto school, only then they will be ready to attend any meet.