I'm currently not using the sounder of my TZT12L and instead use a DFF1 and an Airmar B117 transducer. Is there any point in installing a switch box with the B117 so it can be used with either the TZT2 or DFF1? I'm thinking more in terms of a backup plan but I'm also curious if the TZT2 sounder is any different/better than the DFF1.