Always good to have a place to store a canoe. Personally, since you are not driving down the road, facing 95 MPH wind (yeah I read how fast you drive) you are not going to need those tie down straps. Just reach up and tie off the canoe from inside to your brackets. So what if it moves around a bit. It is not like it is going to fly off. Also, I would put a bike lock on it too. If you remember my 2 kayaks in my trailer, they always had some heavy cardboard under the tie down straps, to help distribute the straps contact with my kayaks. They are out of the sun, but they do deal with long periods of being strapped to the wall of my trailer.
b