I don't like to be left hanging, waiting for a thread to provide a solution so I decided to let those who are interested know about the leak I had from my Dansk fuel tank.
It was the fuel level sending unit gasket (cork) leaking at the top of the tank. It was actually hissing and spraying around the edges, so I asked a mechanic I respect. He suggested that cork is useless in this application unless everything else is perfect, including the vapor vents.
He said, "1.) Check the tank vent tubes to the vapor vent cannister, 2.) buy some Felpro Karropak and make my own gaskets, because It's supposed to be impervious to gasoline, and 3.) buy a tube of Permatex White High Temperature Thread Sealant and coat the gaskets and threads with it before installing the fuel level sending unit. So I did all that, but I doubled the gaskets with the Permatex between them, to make them thicker like the cork was.
I discovered, "1. One of the tank vent tubes to the vapor vent cannister was plugged solid with "who knows what?, probably fuel varnish or CAD plating flash," and had to be cleared with some galvanized steel wire as a flexible ram, 2.) the Felpro Karropak is expensive but it really is impervious to gasoline, and 3.) the Permatex White Thread Sealant is also impervious to gasoline and, with the cleared tube, completely stopped the leakage and the gasoline smell.
I hope this helps someone who might be worried about fuel leaks from a Dansk tank.
Tom Kizer