Each presenter must have their own lavaliere microphone Ceiling speaker systems are normally inappropriate for speaking engagements. Use your own system or rent a system that will insure quality sound to all attendees. If recording a session please place microphones in the audience in order to pick up their responses. Speakers should be placed in the rear, middle and front of the audience. Studies have shown that a presenter that is illuminated produces a much better session.
Audiences tend to listen better and be less distracted.
Do not over seat the room. It is always better to have every seat taken then a sea of empty seats. The seating should match expected attendees or fewer and therefore will create the need for the audience to be seated up front. Place the front row seats no more than six feet away from the stage if possible. Make sure that members of the audience are notified to turn off all electronic devises that may interfere with the presentation prior to the start of the session.