Mark H.

Correct, strap the blocks to the kayak first, then load on the car and then secure kayak to car. Bow and stern lines set to dampen movement, not to prevent movement.

I used the below set-up quite successfully. That pic taken in St Augustine, FL, I live in VA. A little additional noise inside the car at highway speeds, and the straps have to be given a twist else they sing, loudly. Biggest issues were folks pointing at me, and rain had a tendency to wick in along the webbing into the Mustang and drip. 

Mark