Thanks Roger
It seems that part of the plan is missing, the building instructions ought to be on the right side, but now I understand a little more. I could never have guessed that the four balsa parts with a little slot were supports to give the wings it's dihedral.
I also found an error in the kit: The numbers on the formers for the fuselage jigs are wrong. If you install the formers in that order you will get a very interestingly shaped fuselage. It might help to put the print on the other side.
I have decided to build the model, it will probably not survive another 50 years in the box anyway, but also to try to make moulds to make a lighter version of the fuselage, so I guess I will start a new thread in the building section when I get that far.
Gunnar