Moving on to closing up the ends of the outer seat riser... Quite a bit of stretch to get this corner to match up to the seat riser...
https://www.youtube.com/watch?v=wzorB_hwLZM
Then the corner was Tig welded in place and another test fit with the bucket seat..
https://www.youtube.com/watch?v=kf-X5eHc5bE