The wing tips are attached with screws into the plywood sheeting on the nose and between rib #10 and tip. The plywood is not really thick enough to hold screws, putting some blocks under the plywood seems necessary. Once I glue the plywood on the wing nose it will be impossible to add these blocks so I better do it now.
I grabbed some 1/4″ x 3/4″ RS-5 piece of scrap wood and cut four 3/4″ long squares. I put each on the side of the nose rib and tracef the rib contour onto them. Using the sander and some channel lock pliers I sanded this contour into the block.
Now each piece follows the contour of the rib.
Before gluing these on I weighed them, a whopping 0.144oz. I think I can live with this weight gain.
I used a small file to remove the varnish where these blocks are placed then glued them with epoxy.
Once the glue was dry I varnished the blocks except for the side that will be glued to the nose plywood.
Using a straight edge I ensured the blocks were not higher than the ribs and filled as necessary.