Insist on Knowledge Transfer during your Engagement
Even if you'll be engaging with a consulting company like Cloud P. Consulting to help guide you through the design and implementation of your EPM solution, you should consider appointing both a technical administrator as well as a business application administrator. These people can work side by side with your consultants ensuring the right level of knowledge transfer throughout the process. The business application administrator should have a good level of knowledge of the Project and Portfolio Management discipline, but also some general knowledge in application configuration. Although there are technical skills required to set-up a SharePoint farm for a Project Server implementation, for the most part, once the initial architecture is in place, if it is designed for scalability, the need for a buisness application administrator is more important than a server administrator for evolving capabilities over time.