The builder's manual instructs you to attach the main ribs to the front spar with the manufactured rivet head against the rib flange. Image1 shows the inboard end of the right forward spar looking outboard. You can see five rows of rivet shop heads. Bending the front rib flange outward before riveting will give you the needed access for riveting. The rib flange can be rebent to a 90 degree once it has been riveted in. After all the ribs are riveted to the front spar you rivet all the ribs to the aft spar. I also constructed the fixture for holding the wing leading edges during their construction. Image 2 shows the fixture. Lastly I set up the jack post needed to take out any midspan sag in the spars when they are on the assembly fixture. Image 3 shows a piece of all thread with some nuts, washers and wood blocks. The all thread passes through the aileron pushrod hold in the aft spar. You just adjust the position of the nuts on the all thread to take out any spar midspan sag.
