I wait an hour or more, it depends on how long the boss spawns. How you farm them is like any other boss in the game. If you have Pika v1/v2, you can use light ray to kill them easily. but I prefer using my high dmg build, but if you don't have the items or pika, you can still kill them because they're really easy. PLUS you can server hop and try your luck finding a public server that hasn't killed any of the bosses yet :) note: you can watch my other video killing all 3 bosses, its better to see how good the build actually is against them (sry for the yap)