—Companies formalize software processes as a way of organizing development projects. Since there are differences in project contexts, a one-size-fits-all approach does not work well in practice. Some companies use a family of a predefined processes, but this approach has a high process maintenance cost. Instead, we define Software Process Lines (SPrL), where a general process with variability is tailored to project contexts. ModelDriven Engineering (MDE) provides a formal framework for defining the models and transformations required for automated SPrL tailoring. However, this approach requires the definition and co-evolution of various types of models and tool support beyond the skills of process engineers, making the industrial adoption challenging. This paper shares our experience using a megamodeling approach to the development of the back-end of our toolset. The megamodel provides a uniform mechanism for process definition, variability, tailoring and evolution, and we hide...