Rounded over the other gooseneck. With one rib removed, you can see there is about 3/16" clearance for the gooseneck to move up. I'll use 1/8" of that for vertical movement leaving about 1/16" for clearance between the nose of the gooseneck and the underside of the skin.

I noticed the gooseneck wasn't quite parallel to the rib.

So, I clamped it up and used a crescent wrench to twist it into parallel.

Okay...so here's the spacing for the popup tipup arm.

...and as I noted on my last log entry, the gooseneck is too wide.

to think the gooseneck arm down, I sharpened the handle of a file and used it to scrape material off the face of the gooseneck. This is quite similar to how ways are scraped when refurbishing a machine tool such as a milling machine.

Fits now.