I guess I not the most qualified to answer but others can always correct me.
CF's are divided into two parts. First part is where the jury examines cocks, size and spa treatments. Basically more is better.
Second part, where the girls come in, examines the three skills you can train at the outhouse. Again more is better and this second part can well tip the contest in favor of a player with a smaller dick.
On top of that the players acquired mojo and trophies will also have part in the outcome.