Humminbird 737 which transducer? quad vs wide side

[KENPCPILOT]

I have a Humminbird 737 with the quad beam transducer. I am going to try it with the wide side tranducer on my trolling motor. Is there really much difference between the two. I primarily use the fish finder for trolling and finding fish and thermocline. Also is the fish finder realiable for finding the true thermocline vs an actual underwater thermometer?