Today I sprayed the primer as required, assembled the ribs & started the task of sorting out the rib flanges. The new ribs are poorly formed in that the lower flange is wider than the upper one, this causes the holes to be misaligned with the holes in the skin. This may have been part of the problem originally as the ribs want to twist inside the skin producing an unsightly result. I'm getting there but it will take a few hours more work before it is anywhere near being ready to rivet.