I seem to recall that they lined up 3 or 4 abreast and then took off, one after the other. There used to be a little observation area/parking lot at the western end of the runways, along Lindbergh Blvd, that was terrific for "bird watching". They have since expanded the runways and Lindbergh Blvd is now a tunnel.
94th Aero Squadron restaurant at the eastern end of the airport used to have good views too...