all depends on your quarry....................
myself i mainly shoot rats, occasionally i get asked to cull a few ferals, so i re-zero for them...
rats - i zero at 15-20yrds max, i lamp them so i manage to get close.
is yours a springer or pcp....????
mines a pcp falcon so i pace out 20yrds, set 3 targets, small med large, then at 10 yrds 3 more, same again S, M, L.
start at the large see where your grouping is with say 5 straight shots. i tend to use the dustbin to lean on. then adjust if required untill the grouping is good and centered. when your happy try the medium, then s