Personally, I'd use a dribble of high temp sealant all round as, I changed mine a while back and it started to weep not long after again. Needless to say, I didn't use any sealant !
Apply a thin line to the gasket groove in the head and again to the gasket groove in the rocker cover, before fitting the gasket. Don't forget the 4 spark plug rings too !
I also found it useful to put the rubber washers/spacers that go between the rocker cover and the fixing nuts (on the studs) in some hot water (near boiling) as, that will bring them back to shape !