Put vinyl around the front of my last 5th wheel, came in very handy.
The twist clips , were mounted with very short screws and sealant applied to each hole. You have to use caution if doing this yourself.
You will need to drill a larger hole if the screw is going through into aluminum frame work rather than just into the fiberglass. If you don't , then you can break the screw off very easily , don't ask me how I know
, in four years I never had a problem with the clips ; other than running my fingers into them when waxing the cap.