Doug, I used 'pinchweld' as a term to decribe two panels that are spot welded together to form a flange such as the windshield retaining 'lip'.
You could do worse than shoot Alan a PM.
He's gone through what you are and If memory serves me correctly he documented his work.
It sounds like a common problem with 2nd series trucks.
Give him a holler,I'm sure he'd be glad to help in any way he can..

1950 Chevy Advance Design 3100 in Scotland
In the Stovebolt Gallery
More pix on Flickr.
I've definately got this truck thing in my blood ... my DNA sequence has torque settings
"Of all the small nations of this earth,perhaps only the ancient Greeks surpass the Scots in their contribution to mankind" Winston Churchill.