Should i range them or melee them with slave? I want 75 range for fight caves but i dont want to waste time on them by ranging if its going to be very slow.

Melee with salve, they arent good to range.

melee. its a lot faster and i heard about safespots being removed.

No point in ranging them unless you really need the xp. You'll get hit just as much (If you aren't praying) and if you're using prayer boosting gear it's better off that you melee anyways. You'll kill them alot faster using whip+salve.