I see that a lot,....going the full panel route. And I've already been that route on the driver's side. I ended up giving up and taking it in, but I was also replacing the tail light panel too. Just too many places not lining up right. I've never done a skin yet, but it's less places to have to line up. I can get a skin on sale for $83 with free shipping. It only cost me $50 after kicking in a gift card (I bought the skin today), so I'm out little if I trash the skin. Which, by the way, I don't intend to do.
Since the full weld still has to be made along the entire flange joint, I would assume it's not as prone to warpage since you're welding over a lot more metal at this point, as opposed to a butt junction?
Someone feel free to add recommendations or corrections to my strategy...
1. Carefully remove spot welds from all the necessary areas (door jamb, wheel house, tail light panel). I grind the spot welds out to keep the original mating surface intact.
2. Cut old panel out 2-3" below body line.
3. Tape along body line on new panel and cut about 1" below the line. The tape is spacer to maintain consistent distance. I might use a plasma cutter to make this cut so it's nice and clean.
4. Fit new panel and screw in place in door jamb, tail lamp panel, and wheel house.
5. Scribe along old panel where new panel meets it.
6. At this point I can attempt a flange seam, and if I bomb it I still have enough metal to go butt weld. Remove new panel.
7. Cut excess off old panel so the distance from the scribe line to the cut is the depth of the flanger throat.
8. Punch holes in new panel and reinstall. Plug welds every 6 inches? And then close the seam junction with hop scotched tack welds, allowing natural cooling. This means it'd probably take multiple attempts over the course of multiple days before I get the entire seam welded continuously.
The thing with my butt welds is they were never the prettiest, but they never had to be. They were always in inconspicuous areas where it didn't really matter. This is scary to me though