I decided to make the patch in several pieces and then weld the pieces to the car one at a time. First I made patterns for the pieces out of poster board. The first piece was sort of C shaped and covered the other panels of the pinch weld.
Here's the pattern for the second piece.
Here's the pattern for the third piece,
Here's the pattern for the fourth and final piece.
The next step is to take thes four cardboard patterns and transfer them to 18 guage cold rolled steel.
This box of scraps from larger projects comes in handy for little patches like this.