No, you shouldn't have the side view mirrors adjusts so that you can see down the side of the vehicle for any reason. When your sitting normally in the seat looking forward, adjust the rear view mirror so that it is level and squarely places the rear window in your field of view. Then, look at the far edges on either side of the rear view mirror and note what you can see behind the vehicle completely to the left and the right. Look in your side view mirror now and adjust the mirror up and down to accommodate your height. Then push the mirror outwards until you cannot see anything that you could normally see in the rear view mirror. Visual information in the side view mirrors should not duplicate anything you can normally see in the rear view mirror. If, when driving, you need to see straight back down the side of the vehicle for any reason, all it should take is a slight head bob to the left or right to change your perspective through the mirror. If this is not the case then it is not the mirror fault but in fact the seating position that is your problem. Adjust the seat to put your head and eyes in the best possible position to see outward.
Using this method you should be able to take optimal advantage of the entire surface area of your mirror. If you duplicate information in the side view mirror that you can normally see in the rear then you are wasting valuable mirror space and increasing the blind areas around your vehicle. Think about the fact that the majority of the time the vehicle is in forward motion. Don't adjust the mirrors to improve your site when driving backwards when in fact your only moving this way maybe 5-10% of the time.