I don't perceive an appreciable diff between two Steelshoot B zone targets. I think both would be OK, as is IPSC target that appears to cover more of interesting structures. I think USPSA A zone is a bit too generous in its upper part. I wanna be simple and say anything center mid chest is good.
Or simply switch to 10 mm and just put it somewhere there, it'll blow their hearts out.
Sorry, couldn't resist 😅