Yes steam leaking from one of those can be a bit nasty.
There is no prescribed sequence for tightening but gradual tightening from near opposite sides until fairly firm with a short hand spanner I think is the way to go. No torque is mentioned in the Field & Base Repairs nor in the Inspection Standard.
As for the grease it is defined in EMER POWER P134/27 "Refit the cover after lightly treating the sealing ring with H1/6850-99-942-4829 silicon compound"
This has been reclassified from a miscellaneous chemical speciality to an electrical insulating material hence H1/5970-99-942-4829
This is XG-250, which benefits from freedom from corrosive action on metals & its effect on rubbers, waterproof sealing properties, electrical proof strength, power factor, permittivity, evaporation loss, low temperature & storage stability.