I'm looking at installing a second depth finder on our boat and would like to tap into the experience out there so I can get the best model. We fish Halibut a lot so need really good resolution and quality at the bottom so we can distinguish between the arrow tooth flouder that also live in the area. We also want to install it as a through the transom model so that it can't be damaged when trailering as we travel 2000km each way.