finished the Stab Spar today by trimming and drilling the last holes. I measured out the placement of the ribs and lined them up to get an idea of correct measurements. The designed used "on center" for some alignment and from the starboard or port to out side edge for others. Very confusing. So I started from the 3 5/8" centerline measurement and the 7 1/4 center measurements and worked my way out. This gives me a good idea of where the ribs will be glued. I marked the spar and over the nest few weeks will get all the pieces together before assembly.