Tonight I roughly cut out all but one 3 ply ribs, then selected rib BL 75 for a trial fit. The templates actually were pretty close. The strings helped to get the rib edge within 3/8 inch of the outer edge of the lower wing skin, that is where it will be. What? The lower skin? Well, first mistake on the wings. I figured that the larger vent holes were for the gasoline and the smaller were for air vents. So that's the way I built it, with the larger holes down. But down is up. Oh well, if it doesn't fit if I turn it around, I'll just enlarge the smaller vents a bit. Should be symmetrical, right?