I have a Lowrance 527c df. About 4 yrs old but just now getting installed. There is the main transducer but also, there is a paddle wheel speed/temp unit that is included with this model. The main gps will give me speed...right? I am wondering if the extra effort of either drilling a larger hole or modifying the one for the transducer is worth it to mount the speed/temp thingy. I'm in Alaska and don't need a thermometer to tell me the water is cold. I'm very much the rookie, though, so I could easily be overlooking something significant. Should I install it or leave it in the box?