When I was building my car - about eighteen years ago and Ray may have different sacs and clips now - I got a set of the plastic sacs (didn't know that's what they were called) and the spring steel clips. The clips seemed to grab the sacs properly by themselves. The sacs seem to fit the holes in my door properly but when I tried the new clips, the sacs didn't want to grab the clips. I am at a loss to explain it. I've been using my original clips and sacs.
I haven't tried it yet, but I might try Velcro. Hopefully, it wouldn't push the panel out from the door significantly.