I wouldn't want to start shimming scopes once set for shorter distances, for me it's too much of a faff.
I shoot 50m and 75 yard competitions at our club and once my scope was set for 50m I decided to use all the mildots available plus any marks beyond the target as aim points. At 75 yards we use a 7" diameter target from https://www.targetz.com and we aim at brick joins on the wall behind or you can place a post behind the target with marks to aim at.
Chairgun allows you determine pellet trajectories and determine how much the pellet drop will be at various distances which can then be tested in the field.
hth
Jim