having more than one screen will depend on the size of the screen and that size of the congregation along with the area you are projecting to and from. you have to remember there will be a few that try to look at multiple screens at first, just to compare them. try first using a screen large enough to be seen from all angles of the area you intend it to be view from. if you must use more than one screen you should to be sure to place them where veiwing area is set equal and not to overlap more than 10% of the center veiwing areas. the benefit of multiple screens means more veiwing areas, the downside to many screen can become a distraction and may require more equipment.