This really depends on your needs and goals for the event as well as the expected reliability of any other crowd sources. Events we typically work with request anywhere from 5 to 250+ members in attendance.
Our recommendation is typically to be a bit overzealous here. In terms of the number of Surkus members you’d like to attend, we recommend ordering more than the minimum number you need to account for any members who may not make it due to last minute circumstances. You will not be billed for any members who do not attend.