[Wiseguy59]

Wils is on the right track.
Get the quarter in the right place, and make the wheelhouse fit.
I spent a lot of time working on that small area to get it as tight as I could.
The second side went easier.

 

[Wiseguy59]

I don't have any pictures.
But I do remember that I bought a lower wheelhouse patch and used a small part of it.
I clamped the wheelhouse patch to the trunk dropoff, like in your photo.
Now you'll have to slice the wheelhouse and bend it outwards to meet the quarter panel, and clamp it.
Once both sides are anchored, cut a metal patch to fill the open area. This is what I used the lower patch panel for.
It's a cut-and-paste, but with metal.
It took some time to get it all, and you'll never get it perfect, but the fit was good, and seam sealer hid the welds in the tight areas.
The most important thing is to anchor the wheelhouse at the quarter and trunk drop, then the rest gets filled in.