Aprill 2020: After removing the old upper structure i started with new tubes inserted into the structure at the rear spar, heat was applied and the new tubes bent down to parallel ( almost) the upper longeron ( which will be removed later for the door openning)
The front spar cross tube was fitted, then the corner uprights and the top x brace. These are all tack welded after much measuring and adjusting to get things squared up.