I used to have a Lowrance FF and Humminbird GPS/FF on my old boat. I used the hummingbird for the GPS only as they will interfere with each other giving you a snow/cluttered screen. I have 2 597's on my boat and have used the settings above, except for the saltwater and have found it works a lot better than before. Depending on my speed I do have to adjust the sensitivity until I get on plane I get lots of snow on the screen in search mode.
These have been a great help in seeing more with my FF, thanks Rich.