If the box size is correct now. Why not cut off the destroyed part, re-add the correct length with a butt joint, then box the outside to sister them together? would give a cool plinth effect and solve the problem. If you don't want the plinth, could scab over the seam inside with minimal space lost. Option 2: just rock the size they are and if not satisfied, revert to option 1.
If I had my old computer I would have the parameters you gave me. As I had them uploaded in Winisd.
I DO have the modeling graphs uploaded on here now that I think about it...