Definitely set aside 2 - 3 hours for your CCP at the Metro substation. It is frustrating to only have one or two windows open for this service! My permit then took over 60 days to arrive, but I was told there would be a delay due to the fact that my birthdate was initially put in incorrectly by the person at the first window.
Adding a weapon to your permit is a shorter wait because they don't need you to go back through fingerprinting and photos. You just make one stop at the CCW window and the revised permit is sent (got mine in 10 days).