RE: CMP Extra 300- 73"
Unless you are going to seriously overspeed the plane and leave gaps at the hinge lines I wouldn't think that the Ultracoat seal would be needed. The surfaces are not that big.
In any case you should apply the seal before you spray.
Try to do the best job you can getting bubbles out of the covering... you can reheat the area after the clear coat has dried, but it works out best if you do all resealing first.