Since no transducer switch is available for the onix, would it be too redneck to just bring the cable ends of the transducers up behind the onix and just switch them when I need too. Most of the time I know the water I am fishing and only need the transducer on the trolling motor. Part 2, would the built in transducer on the terrova give me the best down picture or would I need to put another down transducer on the trolling motor? Thanks