The increasing availability of portable handheld mobile Augmented Reality technology is revolutionising the way digital information is embedded into the real world. As this data is embedded, it enables new forms of cross-device collaborative work. However, despite the widespread availability of handheld AR, little is known about the role that device configurations and size play on collaboration. This paper presents a study that examines how completing tasks using a simple mobile AR interface on different device sizes and configurations impacts key factors of collaboration such as collaboration strategy, behaviour, and efficacy. Our results show subtle differences between device size and configurations that have a direct influence on the way people approach tasks and interact with virtual models. We highlight key observations and strategies that people employ across different device sizes and configurations.