considering weight and cost youd be farther ahead with a 2 HP long shaft much lighter and only need a liter of gas and never have worry about batteries
Batteries are rated in amp/hrs,more the better.Sizes are usually a group 27 or 31 IIRC A large battery kept on the lower speeds will last a weekend if used sparingly.If you like to rip around and have it in rabbit all the time then a battery will only last an afternoon.
You ll want the maximizer as it uses much less battery. 55 lb is enough only need one battery then. I use the bow mount so i can control with the foot pedal but the tiller steer would also work just need tge exstention so you can stay in the rowers seat