Thank You Pythagoras
At least a year ago, in my first shop space that was not large enough to accommodate both wings mounted to the fuselage at the same time, and in an urban environment that was not conducive to an airplane out on a parking lot for a day (at least), I mounted my wings and drilled the rear spars one wing at a time. Sweep was set by ensuring the leading edges were perpendicular to the center longitudinal line of the fuselage by dropping plumb bobs from the leading edge to a string line that was one leg of a 3-4-5 right triangle. Actually it was a 9 ft - 12ft - 15ft triangle. Even though I trusted my math and measurement of string length at the time, I only pilot drilled the rear spar and fuselage rear spar carry-throughs after also setting incidence per the drawings. My thought was further down the line I would have a shop space large enough, or at the hanger, where I could attach both wings at the same time, double check and enlarge holes as required.
That point "down the line" was yesterday. I now have a workshop large enough to house a complete RV. So, my best friend Lanny (fellow pilot and homebuilder) and I hung both wings and went through the sweep, triangulation and incidence checks again. Van's says you should have no more than a 1/2" variance between any two points when dropping plumb bobs from, for example, each wing tip or a wing tip and root point. I had 1/4" or less. My triangulation measurements from wing tip to tail were within 3/16". There was no noticeable difference in incidence checks using a bubble level and the blocked method on the plans. So, I finished drilled both rear spars to 5/16" and patted myself on the back as the bolts slipped in to place. Greek mathematicians would be proud!
While the wings were attached, I needed to fit the wing to fuselage fairings. These are pre punched and fit really well. The pre-punched holes aligned with tank screws on either end of the fairing, and aligned with the pre punched holes in the wing skins. With it all duck taped and cleco'ed in place I also match drilled the tank skins. Finally, I scribed a trim line that will give just shy of a 1/4" gap, to be filled by the Van's supplied rubber molding. The plans say to ensure this gap is a min. of 3/16 and a max of 1/4" but measuring the rubber molding, it appears 1/4" is really the preference. I will slightly undercut my line.
BTW, a sharpie is exactly 1/2" in diameter. So, if you hold it up against the fuselage, its point scribes a line exactly 1/4" away. Thanks, Lanny, for seeing this and making my life a bit easier yesterday.
Before removing the wings (FOR THE FINAL TIME!), I rewarded myself by enjoying a moment (OK, several minutes) of sitting in the cockpit of the plane that is now so close to being ready for the DAR inspection I dream of it. My To Do list is down to less than 10 items (including putting fiberglass in primer). Registration paperwork is filed, I am in a dialog with my DAR and I am on Mike Seager's calendar for transition training in August. Holy cow Batman, the light at the end of the tunnel is so bright, I "gotta" wear shades!
Thanks Lanny for all the help, good ideas, encouragement and camaraderie.