Has anyone used the 798ci HD SI Combo with CannonLink and Digi-Troll 5? Before purchasing the Digi 5 and the cannon link, I wanted to make sure that it will work for How I fish. Mostly I don't understand how the bottom tracking works, does it use the distance from the ball to the bottom? I get the overall idea of the functionality with this setup, but can someone explain how it actually works? Thanks, Dan