Recently done a frame repair on an RT/10, and got it back i spec +/- one mm i tolerance.
Cut out the bent parts and weld in new ones..
You will need a car o liner, or a similar jig for measurement.
And of course the measurements from the manual with date lines.
The worst part was getting off the trunkliner.
Its glued on, and i tried everything to get it off without tearing it apart. even a vibrating air knife
well eneded up with...