I feel that even if you take the size factor out of the equation, Roy would still have an advantage in power. I know the 130-35 Mayweather had good power but at 160-68 Jones had better.

The X factor would be Jones's chin but I don't think Floyd would be able to KO him.

So the way I see it. Floyd has the skill to beat Jones but he will most likely be tentative and have low punch output. While Jones will most likely be flurrying and have a high punch output.

Jones by UD or late stoppage based on work rate and power advantage.