Lets make it easy for ourselves. My system for adjusting my camera/lens combination, for use on my superb NN180, is very simple. I set up the tripod and camera so that they are level. I then choose my near and far reference points, adjust the camera position and finally check to make sure everything is still level. Business as usual. Here is where I simplify matters: I line up my two reference points in the dead centre of the viewfinder and then pan to the extreme left or right (it doesn't matter which) edge. It is now that I adjust my camera on the rail until the two reference points are aligned again. A quick pan over to the other side to check for movement and hey presto, all is done. Once the camera is setup on the tripod, 30 seconds will do it, including tightening the screws. It is so quick and easy, it makes it simple to do on the fly with different lenses.