How Do I Know What Dimension My Screen Should Be?

The width in relationship to the height of the screen determines the aspect ratio. If you know the aspect ratio of the screen image, the diagonal will populate in the box of the Screen Finder selection area. If you know the diagonal, then the aspect ratio will populate. There are many common aspect ratios to choose from and usually the best place to start is by determining the primary source of your content. For instance if you watch a lot of HDTV then starting with a 16:9 aspect ratio would be a good choice. 

When enjoying a two-piece projection system, going big is never wrong. After determining aspect ratios, work backwards from the limitations of the room dimensions to achieve the maximum image size and also determine the masking features that you desire to have in your ideal screen system.