A general quick reference is of no real use.
So what if you set it on 100yds and a hog jumps out at 137 yds? At that point, you either have to look through the scope and adjust it, or just shoot and hope that your cheek weld is correct.
The easy thing to do while hunting is to set your scope to low power with parallax at infinity until you need to make a precision shot.
-- richard