Monocentric multi-scale (MMS) lenses are a new approach to high-resolution wide-angle imaging, where a monocentric objective lens is shared by an array of identical rotationally-symmetric secondary imagers which each acquire one overlapping segment of a mosaic. This allows Gigapixel images to be computationally integrated from conventional image sensors and relatively simple optics. Here we describe the MMS design space, introducing constraints on image continuity and uniformity, and showing howparaxial system analysis can provide both volume scaling and a systematic design methodology for MMS imagers. We provide the detailed design of a 2 Gigapixel 120° field of view (FOV) imager (currently under construction) and demonstrate reasonable agreement with the first-order scaling calculation.