Fuel sending unit gasket

Personally, haven't had any luck with any of them. The gasket or the lock ring. So I use a gasket, but use an aircraft fuel tank sealer with it, it's called Pro Seal. It's a 2 part sealer, impervious to fuel. Never a leak in two cars. I got tired of screwing around with leaks, that's how I dealt with it. It can be released with a heat gun, but probably not in my lifetime.