I've been storing/transporting my Sports for about 2 years with the method shown at my webpages.
Try ...
http://home.eartlink.net/~leinfam/index.html
...to see my setup. The dedicated rack info is on the 3rd page.
This rack has carried the boats about 8000 miles, now, and (so far) no problem with the boats. Please note that I use very thick padding to spread the load in the drive hole (not a strap or rope).
Also, the boats are secured on the drive pins at the exact angle to prevent distortion stress (such as very hot days). The lower straps are tightened sufficiently to slightly reduce load on the support pin.
There is no worry about dropping onto the rudders, because I'm using an electric winch (power in/out) to raise or lower the boats. The ease of use, with this rack, has really enhanced owning these kayaks. It doesn't matter how tired we are at the end of the day...loading and tie down is effortless!
Regards, JimL