Re: guys who USE the shoulder roll
a big difference is that holyfield places his hand between his jaw and shoulder. this squares him slightly, which makes for quicker lead hook counters but ... he's squared up.
-when you show more chest, to slip shift your weight to your back leg, to take your head off center line
toney keeps his right shoulder down and his left shoulder up, with his left shoulder against his left cheek/jaw.
-to slip like toney, because he's so narrow, all you have to do is a half squat and make your opponent's jab go over your shoulders like a weight bar. or, like old lazy toney just bow to your audience.