They would all have been extremely tough fights for him. Lots of different styles. Watson would maybe have been the toughest. I'd have given Benn a 5 round window. After that, I'd have fancied Herol. Eubank could have been outboxed for a decision win. Eubank had a torrid time sparring him in Sheffield, stating after that he'd never fight him. Yes, they all had the power to have changed the fight in their favour. But Herol had the ability to beat them with the right gameplan whilst being high on confidence. Herol could be too negative at times. That could be his undoing. But guys like Eubank didn't like high paced fights against movers.
I think they all give him trouble. I think Benn who I think is great stylistically is easier than Graham or Watson or Eubank.. Benn could be hit and dropped as Doug Dewitt found out, and even against Barkley he was rocked and hit easily.
I've probably favored all three (Benn, Watson, Eubank) over Graham, when previously discussing this combination of match-ups. However, it does seem quite plausible that Graham could turn the tables on these guys. Watson, to my mind, was the best of the lot, however.