We recommend 3. However some tunnels attract an audience that is slightly slower than others and filling the waiver takes longer. You might want to add some more.
You can use terminals to checkin and fill the liability waiver and others to navigate in the photos taken during flying. Its the same program but it can be customized to show either one or both functionalities
Right now we have the space for english, german, spanish, catalan, french. If you need more we can add more.