Hi BH
I actualy own a 70 C10 and a 71 CST C10, the dash I am posting is in a 62 chevy But it nay help with some idea's on your C10
At this point the panel has been welded.
Now with proud of the weld ground we can manipulate the panel and plannish the welds to relieve the heat effected zone.
With the panel plannished you can clearly see the stress is practicly gone.
Next I have to round over the edge so it fits in it's new home.