168, probably. His performances tended to be a lot more consistent and dominant there than they'd been at 160 and he looked fitter and better-conditioned as a Super-Middle than as a Middle...But of course you have to factor in that his less dominant showings at 160 might have been partly down to simply facing a better level of opposition there. But at 168, the Barkley and Williams fights were the best of Toney. He looked uninterested in the sport after going to 175 and didn't achieve that much there, largely due to the hangover of the humiliation against Roy. The one really notable fight from then on where he looked as classy and dangerous (in every aspect) as he did as a Super-Middle was actually at Cruiserweight when he took the IBF belt from Jirov, and that version of Toney could well have cleaned house at 190 / 200 lb on that kind of form...But he went straight up to Heavy instead in search of bigger money fights. So 168 it is.
Probably 168, event though he he didn't face the same level of competition there as he did at MW, bar Roy. But he was in his prime years and had gained a good level of experience and seemed to be in good shape generally. The years after his stint at 168 should really have been his best since he still was only in his mid 20's, but as the previous poster said, the loss to Roy seemed to drain him of confidence and commitment to the sport for many years.
160. Tougher opponents forced him to be in better condition. And at the middle division there was more emphasis on legs and mobility. that became less of a factor as he moved up in weight and suited his game much better.
Interesting to not is that McCallum felt that Toney had improved significantly from their rematch in 1992 to the rubber in 1996. Toney was 28 in 1996 so that would be a pretty natural age for him to be at his peak. The problem probably was his inconsistency.
He had big troubles making 160. He really just wasn't a natural middle. The Tiberi performance was inexcusable and the Reggie Johnson decision was debatable. 190 was probably his best weight.
I’m probably in the minority but I think Cruiserweight. He had some sensational performances at 160 and 168 though so I can see that swaying some.
Heavyweight Toney would have beaten any other version of Toney so that Toney was him at his best. It’s not rocket science you know.lol