When fishing in water 2500' deep, but only want to look at the top 200', I set my machine range to 200' and set gain to manual and adjust as needed.
Is this the way to go?
Yes, that will work. Unlike some other companies, our sounder doesn't need to see bottom to show fish targets. Because you don't see bottom, you won't get digital depth numbers but you will see targets/fish. You might also consider "SHIFT" function (para 7.5.3) in some instances. For bottom fishing bottom lock and bottom zoom would be helpful.