Bart. You have to bend or reinforce all 4 sides.
Are you shaping it up in Pullmax?
I think a good EW would do a good job.
This is a big panel. For the production of such large panels, carmakers bought special huge presses .... It's challenging.
I would bend the edge 40mm up. On all sides. This will reinforce the panel. You can even make the edge bend you need. Then you shape and bend the middle area.
I saw Grace make a roof somewhere. She just knocked on a large reversing machine. But it was only part of the process.
https://www.youtube.com/watch?v=1nLX_elBduU