Quoted from GravitaR:Here's the answer to your question. Hold a flipper frenzy for 2 hours with head to head matches.
Example here:
https://www.ifpapinball.com/tournaments/view.php?t=47036[quoted image]
I would have to disagree with this format based on the data the OP provided. They only have 5 machines, which means they can only use 4 at one time because if you use all 5 you are going to have a bunch of back to back games on the same machine. If you also use all 5, it leaves no room for error if a game goes down. Secondly, they have on average 16 players which means there will be 6-8 people in queue which is way to many for a 16 person event.
Having only 5 machines is the big roadblock. However I would recommend doing a timed match play event for 5-6 hours and whoever is in first when times up is the winner. Use these settings in Matchplay.Events:
Format: Group Match Play
Seeding: Random
General Pairing: Random or Balanced
Scoring: IFPA or PAPA, your choice
Arena draws: Balanced
Duration: No set duration
Matches each round: One match/ Best of X
Tiebreaker: Automatic