The LR manual I have recomends using a general purpose grease, though a friend swears by 'high velocity' grease or making sure the hub is absolutely packed full of grease to prevent the grease being thrown away from the bearings by centra fugal force.
Alas on the RRC hubs (and propbely all later LR hubs for that matter) you can't do like the old series hubs and just remove one bolt from the drive flange to reveal a hole for pumping grease directly into the hub to make sure its full.
