I am not sure that wing/float incidence is really an issue. If you followed Cunningham's instructions, he says to have some positive incidence, and I have found that 1 1/2 to 2 degrees works fine. I suggest that you do put a water rudder on, if even only for the taxiing in case you need to turn and there's a breeze that, without the water rudder, will make the plane weathervane. Also, the water rudder can be very effective until you get the plane on the step.