Sugar Ray Robinson,,mainly because Ray has one of the all time great chins,,Tommy does not. I do think Hearn's could get a win at 154 though, but he's still an underdog.
It'd be the same outcome at any of those three weights. Robinson bombs Tommy out eventually. Possibly by as soon as the mid rounds. Robinson would have to walk through fire to get to Hearns' chin, but he had the chin and the will to do so. The only weight where the outcome changes would be 175. Hearns' frame just carried light heavy far better than Robinson's.
SRR would outbox Hearns at all of those weights, and might be able to force a stoppage. Hearns would probably lead in all of those contests, but then gas out.