Product-Service Systems (PSS) are seen as key enablers of circularity. However, better sustainability performance of PSS when compared to transactional business models is not given and it must be carefully considered in the design process. The early-stage PSS design is considered crucial because it determines most of the future offerings' impact. Nevertheless, manufacturing companies struggle with PSS design and often rely on ad hoc intuitive approaches with low success rates. Current PSS design approaches have been dispersed in literature until a recent systematic literature review by the authors proposed a comprehensive generic process model to enable the inclusion of sustainability considerations in the early stages. This paper takes the generic process model as a starting point and instantiates it to the context of two manufacturing companies, seeking to (i) explore the instantiation process from a generic to company-specific process models to support manufacturing companies; and (ii) reflect upon and prepare an evaluation of the generic process model concerning eight predefined criteria. The study reveals a number of potential areas for improving both generic and instantiated process models.