Back at it...I drilled the screw holes where the tank attaches to the joint plate (the black 5/32" clecos).
I took off the tank (again) and deburred the baffle/rib holes in the Z brackets. (The black tubing shown in the picture is the conduit, by the way.)
Van's recommends drilling the fuel tank (skin to ribs and baffle) off the wing so you don't accidentally drill the spar. I think it would actually be easier on the wing, assuming you take precautions and skip the inboard foot or so of skin-to-baffle holes until you get the tank off. Anyway, the tank is drilled.
Next I bored the tank attachment screw holes out to #19. This was a multi-step process...first I drilled them out to 1/8", then used a Unibit to get 'em to 5/32, then used the #19. I went with the multi-step process because the skin is just "loose" with nothing to drill into.
Then I used a soldering iron and a straightedge to remove some of the vinyl so I could machine countersink the skin-to-baffle holes for flush rivets (since the baffle flange doesn't get dimpled you have to countersink the skin). Got through countersinking the top and called it a night...
