Why not go with these?It turns out that there are stainless zip-ties, who knew?
Would work better to attach 1/2" HC to PVC pipe...those jclips aren't going to do that.
Not fond of jclips...and wouldn't drill holes in PVC as it will weaken it.
Make sure your HC pieces are overlapped by a couple inches on the edges.
Is that single piece installed in pic..and you're ready to add another?
Use screws and washers to attach HC to wooden bottom frame.