I always go to rock lobsters (I burst) with familiarisation bonus and get at least 100 more crims than if i went to waterfiends. I usually get ~250-300 crimsons for the 40 mins and it takes me ~5 mins to get there. (I have 98 summoning banked, to give you an idea that I'm not some random person who bases their opinion on a thing they've done only once.) To avoid losing time, make sure you have a terrorbird pouch + scrolls in invo to get there, use 'burstinglobs' clanchat and their door partner world is w66, so head to w66 @ dungeon entrance and if nobody is there, wait in lobby. Then back in the chat and ask if someone needs a dp (Door partner).