Shortest distance your scope will focus at will work good enough. Just remember that if the distance is 33.33 yards, one 1/4 MOA/inch click will move 1/12th inch on the scale. The range is one third of 100 yards and 1/3 of 1/4 is 1/12th.
In other words, don't forget to use grade school math.
US Navy Distinguished Marksman Badge 153
Former US Navy & Palma Rifle Team Member
NRA High Power Master & Long Range High Master
NRA Smallbore Prone Master