74 Charger Rear Qtr Window Outer Sweeps

I have a 74 Charger that I'm replacing the rear quarter window outer sweeps because the original ones are shot. The problem I'm having is getting the clips into the slots where the window opening curves up at the back of the window. I've tried installing the new ones by starting at either end of the sweep but then I can't get the curved area clips in. I tried to put those in first but it just doesn't want to go in. I have the original sweeps and the clips on the reproduction ones are in the exact same place as the originals. In the photo, the original is on the bottom, a PUI repro is in the center with the back cut edge ( from PUI that way) and the top one is the Top Cat brand. Any suggestions by those of you who may have installed these? The PUI is the most flexible but the Top Cat seems of better quality but doesn't have quite the same curve. The two clips I'm having problem with getting in the slots in rear quarter panel is marked by the two screwdrivers. Any help /suggestions are appreciated. Thanks.
Terry W.

Success finally. I had to elongate the corner clip slots in the quarter panel and the Top Cat window sweeps slipped right in. I used a carbide rotary file and only had to elongate the two slots about 3/16 inch each. I'll include a few photos. Thanks.
Terry W.