I’m not sure about the use of steel targets for handgun training, specifically for counter-offensive handgun training.
Steel presents a magnified version of the same problem you get with paper targets, that being that you get immediate feedback from the shot.
Over and over again I’ve heard and read and seen (in video of shootings) that you don’t see any given shot or shots hitting. You don’t see that you’re hitting or not when you’re shooting someone. At most you see something puff or fly out (the clothing or perhaps dust or dirt). That doesn’t happen all the time, though.
The only feedback you should expect to get shooting an attacker is a change in that attacker’s attitude or behavior. That’s always not going to be instant or immediate like with paper or steel.
Best I can advise to get some idea of how that will really look is to get some shirts and put them over paper targets. That should cut most of the usual hit indicators and give you a better idea of what it will look like to shoot somebody and not some thing.
Now if you’ll excuse me, I gotta go find some cheap t-shirts…