The use of a dual mobile and large screen approach offers a number of intriguing possibilities including a potential solution to the problem of managing conflicts that arise when a large screen is shared in a public setting. Here, we report on a series of experiments carried out to determine quantitative or qualitative effects of user performance when interaction is split across large public and smaller private screens. Our position is that using mobile devices as an auxiliary device for interaction can boost user experience when interacting with large displays.