I just got a Humminbird HELIX 9 CHIRP MEGA SI DI GPS G4N. My current G2N has a Navionics Platinum+ card. Is Lakemaster Coastal better for inshore around Charleston? I go to Lake Marion and Moutrie just a couple times a year and the Navionics covers them well but 90%+ I fish out of Bushy Park or the Ashley River. I’m probably going to use both units