My thoughts are that you set the ADI in any aircraft around the particular attitude you need to fly at that time. For example, if you are going to do an ITO you would set the ADI to indicate level in the hover in your present configuration so you could recognize a three degree nose down attitude for takeoff. Later on, after transitioning into cruise and resetting power and airspeed, you would reset the ADI to that cruise attitude because that is most important to you then. Just my opinion though.