take a cue from CAS here... ( BTW... local CAS targets are often as close as 3 yards )
solid mount your plates with a slight angle downward ( my local club uses a spring in the mounts, that let the plate "ring" nicely when hit ) they do use tip over targets with shotguns, & people are always getting hit with rebounding shot, both because of the tipping over angles, & the slower moving shot )
use only lead bullets ( soft lead is prefered )
if you handload, don't use maximum loads, find something mild to practice with
wear eye protection with side shields
keep your plates as flat & fresh as possible to reduce upward bounce back from crater edges ( a good rough sanding disk on a 4" angle grinder can be used as often as needed to keep the shooting surface "fresh" the thicker / harder your steel, & the lower power your loads, the less maintenance will be need on your plates
even if all this is followed, you will get the occasional hit, but the energy is usually not even enough to break the skin or leave a bruise...
In life you either make dust or eat dust...