Fitz [trap setting punch picker with tremendous power] Sullivan [better finisher ,and more dynamic puncher than Jeffries, quickly into range and a thunderstorm once the fight was on] Jeffries [incredible durability, and good power, but a grinder]
I guess we start by taking away their power. I think Fitz is the one with the most left. Hard to decide between the other two.
Lets put it this way. I dont think that that Fitz can have been more effective than Jeffries and Choynski as a finisher, purely because he hit harder. I think we have to conclude that his methodology was better!
Skill: 1. Fitzsimmons by a mile 2. Sullivan 3. Jeffries Modern-looking skills: 1. Jeffries -- Fought in a crouch with a reasonably modern stance; used the left hook 2. Sullivan -- Basically by default, since Fitz is worse 3. Fitzsimmons -- Stood like a cross between a fencer and a Thai kickboxer riding a horse. It got messier from there.
Interesting thing is Sullivan had the most power and speed but the least skill ... Fitz had the most game and Jeffries was simply a physical adonis of his era ..