Question about Vinyl Top Trim Attachment

I ordered some pieces from R/T Specialties to reattach the vinyl top trim to my '73 Swinger, which was all in the trunk when I bought the car. There are two different means of attachment. First is this:
Trim Clip 4.PNG

Those came with some sheet metal nuts, so attaching them to the car is simple enough, but how does the trim attach to the clip? I have exactly enough of those to do the job and I don't want to sacrifice any experimenting on how to bend that arm.

The second means of attachment is via the studs welded to the sheet metal. I also received new clips for those, but I'm struggling with how to properly insert them into the backside of the trim. I can't seem to squeeze them enough to get them to pop completely in, and if I start by sliding them in from one end, they don't want to push around the curved section.
Trim Clip 1.PNG

Trim Clip 3.PNG
I searched through the FSM for the Body, but I didn't see this mentioned in there. Any tips would be appreciated.