Guys;

I think the trick to having a leak-free result is assuring everything is clean and not overtightening the nut (I only tighten about 1/8 turn past snug!)...after all, it only has to compress the gasket the slightest amount to circumferentially seal against the fuel line...there is very little pressure, just the weight of about a 1.5" column of fuel...

I recall being in a parking lot with a leaking carb (as a result of a disintegrated rubber seal from an overzealous previous owner who tightened it figuring it needed to hold back pressure of the Alaskan pipeline) and super-carefully cutting one of those rubber gaskets for the bowl with an x-acto blade from 3/16 or 1/4" fuel line...it did the trick...as a matter of fact, I don't recall ever revisiting that carb, so I'd say its still holding!

Cheers