Thanks UCS
I have and clear silicone as well. I'm over thinking it I'm sure but if they came off while driving, they CD scratch my trunk deck, or worse come off the car and perhaps cause problems for other cars. If I got them...I'd fasten them as per instructions.... fwiw

 

Either would hold it well, but in the end it's your call. Still a nice ride...

 

I am sure they wd, thanks for your replies