Resumed work on vertical fin. After reviewing the HomebuiltHelp DVD regarding fitting the skin, I opted to follow the advice on the Zenith forum regarding inserting the ribs more fully into the skin and overlapping the skin beyond the spar edge to be trimmed later. I had already done some test fitting before setting the fin aside earlier, so I had much of the alignment mostly figured out. The big rib was positioned at 90 degrees and holes marked from inside with weights on the skin to flatten it. Top rib flange was given a centerline and lined up with predrilled holes, leaving a few milimeters beyond the rib top. Drilled to final size and cleco'd. Since I was working on cardboard and foam over the table, I could cleco the lower rib from the inside when needed and lay it flat with the spar cleco's hanging over the edge. That made it easy to add weights to the skin where needed to keep it flat. Took everything apart to deburr. Also trimmed the skin along the factory provided outline. I took the opportunity to try out my new air nibbler. I love it. I still haven't gotten the hang of the left and right shears, but this thing just makes it so easy and it doesn't bend the metal when eating through a large chunk. Just a bit of edge dressing with a file and the trimmed edge is good to go.