[hawfumat] The luck of the draw in chess

How much worse is a single round robin tournament than a double round robin tournament?  In a single round robin, one can get lucky in the draw in two ways.  The first, well known way, is to get more white games than black.  The second is to get white against the specific opponents for which the color difference is most likely to make a difference, those with a similar rating.

Calculate a "luck" points correction.