I use a grey loctite sealer availible at Halfords find that is very good,and have used it instead of a gasket on my saff(Most new engines which are alloy use this type of sealer everywhere except head,exhaust and intake).

Don't forget to reseal under front cam caps because this can leak too.

Cometic cossie rocker gaskets are very good i have one on my tina No leaks,no probs,no worries

And i've had gasket off four times,just picked of sealer off half moons and edges of gasket and resealed and used it again

Use a torque wrench and start middle outwards.