RE: 4*60 with a wing delimma...
One idea Brian would be to trace the root rib pattern onto 1/8 sheet balsa and cut out two new ribs. Glue one to each root rib of your wing panels. These will add thickness to your root ribs that will be sanded to the proper angle in the next step. Next, prop up a panel so that the tip is 1/2 the total amount of dihedral you want. Now using a sanding block, carefully sand the root rib until the sanding block is flush to the rib. Repeat for the other wing panel. When the two halves are joined together, you will have your full dihedral angle. The trickiest part of the whole process is keeping your sanding block square to the root rib. I hope this helps. Maybe some others will have an easier method. Mark