Had to bend a solid fuel line, dont like rubber hose for fuel to carb, so done the double flare, but had slight leak. Found online thru grainger they sell copper flare gaskets in various sizes. Sealed it up perfectly.
Good to hear you got it sealed up. Double flares are used in high pressure applications like brakes that operate at 3,000 psi compared to a fuel line that works at only 5 psi. A single flare would work and requires less torque to seal. If you over tighten a steel flare line you risk cracking the aluminum case on a tranny, or ripping the threads out of a pot metal carb body.
The setup that I had on there was a single flare duel feed that i always had to use teflon tape on the threads to get it not to seep. Put on the y block and the small fuel lines to carb sealed they had a double flare, but my line I bent seeped. Nobody at parts stores ever heard of flare gaskets, but glad I found them. They sealed without having to over tighten fittings.