3 - Depends in what type of mob you´re hunting. If you can kill it with 1 nuke, goes all the way with garment to use the 20% mana reduction. But if the mob have some strong phys attack and you must tank a hit or 2, so I suggest using armor.
4 - IMO thiefs are the way to go, with a high lvl nuke you can kill the horses/camels with 1 nuke and kill the hunter/merchant with some combat tactics. One day I saw 5 nukers thiefs in a rampage, they are deadly because they nuke from all sides, all of them is affar from the other, so when they attacked the person is caught in a surprise attack, with 5 different nukes coming from 5 directions.
Long range attacks are the best friends for nukes ( and archers too ) .