Got my first boat finally after a months of search And I got a Lowrance 7X HDI and a Lowrance Elite 5 basic model. I am planning to sell both and would like to advice what to get. Helix 7 maybe or a lowrance 7 chirp? I am looking a big screen combo under $800 . Want to fish on lake and in the bay in salt water.Doesn't know too much about pro and cons, so please help me out.