Mr. L, I am really enjoying your work again this year and love your testing methodology. However, I think there are some better things you can do in regards to measuring the effectiveness of corner routines. Instead of taking the total number of goals scored over the course of the season, you should really be looking at the total number of corners for each tactic then determining the ratio that was converted to goals.
For example:
Tactic x generates 400 corners over the season, scoring 15 goals.
Tactic y generates 300 corners over the season, scoring 13 goals.
Tactic x has a success ratio of 400/15 or a goal every 26.7 attempts.
Tactic y has a success ratio of 300/13 or a goal every 23.1 attempts.
So while tactic y scored less goals over the course of the season, it was actually more effective over the course of the season. Total goals mean very little if it takes you more corners to get there.