Help installing Yakima tracks and landing pads

I’m putting tracks and crossbars on my camper shell. Before I begin upholstering and repainting it, does anyone know if the landing pads pictured below have to be drilled through the fiberglass as well as the tracks, or just the tracks? How does the landing pads mount into the tracks?

 

The landing pad attaches the the track with two screws. The towers snap into the landing pad.

 

The square nuts slide into the track.

 

Can I make a suggestion?
You may want to reinforce those racks on the inside of your cap.
Here is what I did...

I mounted these Yakimas on top of my cap.



And secured the mounting flanges by bolting them through to Heavy Duty shelving brackets I had laying around with big fender washers to the underside of the cap roof
It created a strongly integrated rack system.

 

I think you’re over doing it

 

LOL likely true,
But as an architect i looked at it this way:
If you have got a canoe well strapped down onto your carriers and you find yourself driving in
60+ winds where do you want the benefit of your doubt, in your strapping or in your carriers?
You can always increase your strapping...

 

The mounts you used are different. Those require reinforcement. It's unnecessary with the tracks.