I HAVE A 998 WITH TRANSDUCER ON BACK AND NOW HAVE A 859 THAT I WILL BE USING FOR GPS AND DI FOR BACK ALSO,I WANT 998 MOSTLY FOR SI VIEWING SO WHERE WOULD BE THE BEST PLACE TO MOUNT 859 DUCER WITH LEASE INTERFERANCE? IF YOU CUT OFF SONAR ON EITHER ONE,WILL DI OR SI STILL WORK IN ORDER TO CUT DOWN ON INTERFERANCE?