Do them all at once
I struggled also and by the time I finished the tanks had a great system.
First, ensure the rib edges are square and you've deburred the flanges well because any sharp edge will catch the skin. Flute ribs to get the line of holes extremely straight--only close and you'll be fighting it later.
Second, set the skin atop the cradle and put one cleco in the bottom leading (front) hole in each rib. This should hold them roughly in place. Next, go around to the top side and put clecos in the leading two holes. As Mike said, you can "catch" the rib holes at a slight angle. Go back to the bottom and put in a second cleco.
Then, shove the leading edge into the cradle. Now work up from the clecos already installed to the back edge, alternating top and bottom. Shouldn't take more than a little wiggle to find each hole.
When it comes time to seal and rivet the tanks, do just the three middle and move the cradle to add each additional rib outward. The proseal actually seems to help them slide in, although the dimples required a bigger spread.
Not the only solution but worked well for me. Good luck!!
Alan
RV-9A Fuse
N984AW Reserved
