You may want to consider a dual beam device, i.e., Garmin 400C. Cone angles are 14 degress & 45 degrees. The wider cone angle is helpful in seeing your spoons, jigs, and etc. when fishing in less than dead calm water. Terminal gear will be harder to keep in a narrow cone angle.

With that depth finder I was able to see my small swivel I had 24" above my spoon at 40 feet. I have no info on Lowrance or Hummingbird.