Hey Guys,
I used Permatex Ultra Grey. I ffilled the groove on the rocker cover edge with the sealant
and squeezed in the rubber gasket. Then I also applied a layer of sealant on the cylinder head edge when rocker
cover sits. I left it for about an hour to cure partially and get "tacky".
Then I fitted it and left it for couple of days to cure properly before starting the engine.
It's been more than a month and no more oil leaks from the rear end of the gasket.