If you're working with a load you know to be accurate, I would sight the gun in for a distance were you would most likely expect to take a shot at. If that's 50 yards, then sight it in for 50 and then test 25, 75, and 100 just to see how the groups react, wind affects the round, and how good of a shot you are.
Remember that just because you can shoot 4 inch groups from a rest at the range at 50-75 yards, doesn't mean that will happen in the field. I'm not trying to belittle your skill, just saying that during the hunt your adrenaline can kick in and make things a bit more chaotic.