How fast the text on the screen goes depends solely on how long the video box is in the Timeline. If you want the credits to go by rather quickly you can shorten it up, and if you want it to be slower and more dramatic you can stretch it. To make it look very much like standard move credits you want the text to be relatively small, the lines to be close together, and to move very slowly. To do this you set a small font size in the control setting, lower the spacing, lower the leading, and stretch the actual text clip out significantly. The best way to use the scrolling text is to put stationary text slates at both the beginning and end, for above the line positions and copyright information, respectively.