My LS has done the 50 cap for earrings as well as the uncapped, both with full alliances.
Uncapped with 18 people is a hoot. Not challenging at all, but it's just nuts with a small army of NPCs running around bashing the crap out of the goblins. Doesn't really take much planning, just make sure mages are healing the NPCs, since your loot at the end for any garrison depends on how many NPCs you have left alive.
For the 50 cap, what we found to help basically was having multiple tanks (preferably NINs) able to keep several of the demons busy. It's very hard to actually sleep the mobs because the NPCs will just come wake them up.
To get some rest time between waves though, have a tank pull a demon far from the outpost while you're still fighting other demons. What you need to do basically it pull it out of linking/"aggro" range of the NPCs so they don't kill it before you're ready to end that round. Once people are set to go, bring it back in range to kill it.
Things can still go wrong, but in general it's not too bad to do with a full alliance as long as you don't just try to zerg it (leave that to the NPCs).
XI Wiki


