09 adjustable tie down anchors

So, has anyone run those plastic anchors through their paces yet? I need to haul a 400lb sportbike about 1000 miles a couple times this summer and am a little sketched about these things being plastic.
Does anyone have any good/bad experiences?

 

If you do the math there, 4 tiedowns and a 400 lb bike, with the angles involved there is never going to be 200lbs on any given point. From my experience hauling my bike, the tie down breaking concerns me a lot less than how much the rail flexes when you have anything pulling on it from above or below. Having said that it has worked just fine every time I have done it.

 

Outstanding.
Thanks for the info.