Just ordered a Lund 1040 Jon boat and need to shop for a trolling motor. I have used a 30 lb before on a similar size boat but was wondering if its worth the extra 100$ for a 40lb? Of course if money wasnt an issue Id just get a 50 lb but dont want to spend any more than I have to. Will likely be about 500 lbs for boat, gear and two guys. is there a big different in power in the wind with the 40 and how much quicker would it kill the battery?