I think buying a kicker locally would make more sense. What happens when you need some work on it, You will be first in line if you buy locally. If not bought from them they may not treat you the same. Just saying. I would give the guys at Melvin Village Marine like Cool Water said. They know their stuff.
FWIW I had a 20 foot alum boat that went 6 mph with a 6 hp merc 4 stroke. I dont think you need any more than that.
Please contact me for the Controllking unit. If we make one for the kicker you decide on it will be $209. shipped from the manufacturer to your door.
I am the local Rep. for Controllking.