When building wings from plans only tracing paper and construction paper is your friend. Trace any ribs you need with tracing paper and then glue them to heavier construction paper to make templates. when you cut ribs make sure you start from the thickest partsof the ribs and cut to the thinner parts of the ribs. You do this in case when you are cutting the ribs that the knife splits the wood along the grain. If the wood splits along the grain then it runs away from the rin instead of splitting the rib. Hack saws work well for cutting plywood pieces but you need to finish them up with sand paper and a file. Buy wood from balsa usa if you need a lot, they have cheap wood but you have to get past the 9 dollar delivery charge. Take your time the hardest part of building the wing is cutting the ribs. use construction paper to make templates to fit any joiners.