Just got a new boat and am trying to decide on a trolling motor..Should I do a 12v with 2 batteries or a 24v setup ? Boat is a 16' Aluminum with a Merc 40..Total weight is 760-800 lbs with motor. I know I want a RiptideST with Ipilot so Im looking at either the 55lb or 80. Will be using this in both fresh and salt. I know you can never have too much power but do you guys think the 80 is overkill ?