If the text is selected (in the title designer), there will be an icon at the bottom that lets you center the text. A menu will drop down, so you will be able to see your choices.
As for the duration, if you change the duration of the title the action, whatever that might be, should slow down proportionately.
You can also go into the title designer and fiddle with the keyframes to change the duration of the behavior. For example, you might want the "action" to move at normal speed but the text to stand still for most of the time. You'll see two keyframes, and the "stand still" time is the time between the two keyframes.
Jerry Schwartz