Jeff has good advice about securing the kayak to the racks not the J hooks.

The finish you used should do fine since you don't store the boat in the water. If it hasn't given you a problem so far I would do a light sanding and cleaning then give it another coat of paint.

It's always fun to build another kayak and the See Bee is a great boat to put beginners in. I have built 3 more since completing the See Bee. A modified See Bee, Kidarka and a Greenland using Chris Cunningham's book.