For digital content curation of historical artefacts, curators collaboratively collect, analyze and edit documents, images, and other digital resources in order to display and share new representations of that information to an audience. Despite their increasing reliance on digital documents and tools, current technologies provide little support for these specific collaborative content curation activities. We introduce CurationSpace - a novel cross-device system - to provide more expressive tools for curating and composing digital historical artefacts. Based on the concept of Instrumental Interaction, CurationSpace allows users to interact with digital curation artefacts on shared interactive surfaces using personal smartwatches as selectors for instruments or modifiers (applied to either the whole curation space, individual documents, or fragments). We introduce a range of novel interaction techniques that allow individuals or groups of curators to more easily create, navigate and share resources during content curation. We report insights from our user study about people's use of instruments and modifiers for curation activities.