Dope has nothing to do with dialing. When you hear "know your dope" it basically means knowing your ballistics, IE, knowing what happens to the bullet after it leaves the barrel. So if you zero at 250 yards, and know where the bullet is at 25, and adjust accordingly (dialing, or holding) your good. If you zero at 25, and know where the bullet is at 250, your good. Obviously my first post was exaggerated to drive the point home (no one zero's a 22 at 500), but I think folks get the picture. Mathematically no zero is better or worse than a different zero as long as you know your ballistics.
Ideal, but that's a little trickier since almost no range has a 75 yd setup.