Quarter skins on '72 Olds 442

[cdrod]

I have finally reunited the body tub and the frame on my '72 442 convertible project and am now moving on to replacing the quarter panels (which have lots of bondo and the normal rust holes behind the wheels. This is my first experience with quarter panel replacement so I don't want to bite off more than I can chew. I've studied the car carefully and decided not to attempt full quarter replacement because the door and trunk gaps were good and I don't want to mess these up. I've purchased a pair of quarter skins and plan to flange and overlap the panels along the upper body line and at the door jamb, and then plug weld where the factory used spot welds inside the wheel openings, at the trunk drop offs and behind the bumper at the rear. This will preserve the door and trunk gaps and the sharp body line along the top of the quarter would be less likely to warp when I tack weld the panels together.

Here is where I need advice and help. What is the best way to attached the quarter skin to the rocker panel (between the wheel opening and the door jamb)? It looks like the factory quarter folded inward and was spot welded or plug welded to the top of the rocker panel. I don't know how to replicate that with the MIG torch, and I don't think the replacement skin is shaped properly to fit the same way the factory did. Should I leave a small lip in the existing quarter and flange it to overlap the replacement skin - like I'm doing along the top? Here's a pic: