how many raids must we do to trigger ex raid
You need about 30-40 unique accounts I think
I think you need 300-400 points in ~1 week (at least it works like that in my town). The formula is: Raid Level x amount of participants. So if you do a legendary Raid with 20 people, you have 100 points.
By that logic raiding 20 raids with 3 people would activate passes
Points look like nonsense, unique players are important
Its a combination of both.
Go Hub has a guide on triggering EX raids