Keep the front sight as low as you can, mostly for maintaining a better cheek weld when shooting at longer distances.
Just because a tang sight has a 3 inch staff does not mean you can get a full 3 inches of adjustment out of it, and also where does the zero mark come out ? Is it above the top of the action or below.. these things all factor in to how much adjustment you can get, then you add the ballistics of your load and then you'll be able to determine how far you can shoot.