I would like to explain a myth here about treasure hunter and NMs: Treasure Hunter does not effect most Beastmen NMs. This is easily proven through some simple deductive reasoning. The majority of the beastmen NMs only drop one item: Hoo Mjuu, Poisonhand, Hawkeye, Mee Deggi, etc. So let's take a look at what treasure hunter does: Increases the drop rate of items. Treasure hunter increases the drop rate of ALL the items a monster can drop. So it will increase the rare drop of a beastmen NM (kote, gi, etc.) BUT it also increases the drop rate of the common drop.
Moral of the story:
Next time you go NM camping, you can use a war sub ^^