To try to answer your questions: I've got an Eagle Cuda depth finder mounted in my canoe. The head is Ram mounted to the thwart in front of my stern seat. The battery pack is in a thwart bag hanging from same thwart. The transducer is silicone mounted under the bow seat. Wiring is run under the gunnel held with zip ties and clips. Easy system to install, and at the portage, all I have to do is turn it off, and rotate the head. The primary advantage this provides is that I can find and follow contours, staying in productive areas easier. I'm sure you'll find fish without one, I just think you'll find more fish with one.

I've never used spinnerbaits with this system, so...

I use this system two ways. One is to contact sspended fish over deep water (lakers). The other is to use it like a bottom bouncer in 15-25' of water. I think the sinker banging rocks invite waldos to dinner.

Also, as a correction to my original post, I meant 'banana weights' instead of 'teardrop sinkers'. I think either will work, but the banana style has less drag.