Idk I used to camp this place for ages pre-eoc and I got one about every ~1m xp in the combat skill I was training. 45 picks in like 42mxp. Never rly done much since eoc it seems a bit faster as they have very low health. I just run around the room hitting everything once so that when they die I get the loot, doing that it shouldnt be very long til u get one.