Hey there Sloth, names James, the Event Organizer for the HT tourneys.
To answer your question, we have been getting an average of 50 people per tourney(including spectators) and an average of 20 people for each game. These numbers do fluctuate though, depending on other tourneys going on near ours.
We should be good on getting set up, Usually have more than enough people to help out, thanks for asking! Do you have a facebook sir? You should feel free to add me or the Hostile Takeover FB, as it is usually easier to get in contact with us through those.