I agree with guros. The duration and setup of how this swarm was made seems ideal, and you can use this as a template for future swarms. Although, perhaps a shift deeper into the weekend would be appropriate? How about some staff checking the logs to see which part of the week has the highest amount of players for 3 days in a row and target those days. Given how much I have played, and that I play at various times of day, I have indeed seen more players online through weekend days.
Tbh, I had originally planned for this to be a Weekend event, but shifted it back a day to coincide with Halloween itself. But I will definitely look into identifying peak activity times for future swarms ^^