Get 85 att, 70 str, 85 def, whipper/boxer. Trust me, you'll get owned by them when you go staking if you make any other pure, just make sure you never get more than 1 prayer.
Just about your tank ranger ideas. Yes they own, i have one, and you better hope you stake like 100m per duel since about 1 person a day duels you since they are so scared. If you dont stake real high theres no point in wasting so much time there.