This is a Humminbird 899 ci HD SI unit. When going over a school of fish in say 30 foot water and the fish were right under the transducer it will split the fish picture to both sides of the screen so where should I place my cursor to mark a waypoint. Will either side do or would I need to place the cursor in the center to get the best waypoint. Will the waypoint change from one side of this 30 foot span that is in the middle of a humminbird side imaging sonar.