I am a little off topic here, but ido think you raise a very interesting point regarding KO percentages. It seems to be at odds with most people's thinking especially when you look at modern fighters who do so much weight lifting to increase their strength, but i dont think that Power and strength is the most important ingredient in knocking someone out. You need a certain level of power, but once you reach this level, speed workrate, stamina and skill becomes more important to get the knockout. This is why Ali (at his best) could keep a 90% KO ratio against pretty good opposition even though harder hitters probably wouldnt have the same results. So in many ways, these three factors (provided you have a decent level of power) are more important than strength in knocking someone out. Does anyone agree?
Speed is definitely very very important. It's the punches you don't see physically, and can't mentally prepare yourself for that knock you out. There is a mental aspect to "chin", and anticipation and reception of a blow is a big part of that. Accuracy and placement of punch and timing can create knockouts as well, which we have seen from arguello and louis(although of course both were physically strong).