I agree that you are probably better off in almost every situation if you pick a shot for each camera and leave it alone! It is such a temptation to zoom in, zoom out, pan a little to the left, then to the right–all in the effort to "improve" the shot. The result is usually that you don’t improve the shot and you create major headaches in editing when you have something important happening on camera during one of your many adjustments.
Two other points that might be obvious to you but not to someone new to shooting interviews…
Set your exposure and focus, then click the camera to manual (this is usually more of a problem with consumer or prosumer gear). The temptation to allow a camera to remain on auto settings will usually cause problems when the camera decides to adjust in the middle of your shot.
Also, put a lav mic on both speakers.
