Today, I finished match-drilling the stiffeners for the Left Wing. Again, it's very important to make sure the spar is perfectly straight and not twisted in the slightest, because the spar is acting as a template. Once the stiffeners are match-drilled, and then installed in the wing, the twisting may show up later. I found that magazines (particularly plane magazines) are great for leveling the spar. Unfortunately, while I strived to build perfectly level work tables, I don't have perfectly level garage floors.