Sorry about that guys! I went back and added an edit to the post entitled "Alas, we..."



Now here is what I got out of reading page 265 of Behwaite:



The angle that Bethwaite has measured as being the least drag with most lift, is in the 3/4 to 1 degree range, Windward, tiller pulled toward weather. And he points out that this is same amount of angle that the water passing around the centerboard is deflected by the centerboard.



So, one can deduct from that, that the best angle for the rudder is when the rudder is taking the same angle to the water as is the centerboard is experiencing.



Let's say the boat is slipping 5º and the water approaching the rudder has been twisted 1º by the centerboard. The water headed for the rudder is 5 minus 1, or 4º to leeward of the rudders leading edge. You turn the rudder to weather by 1º and now the rudder enjoys the same apparant water flow angle as the centerboard did.



You set the rudder so that it gets the same angle of attack as the centerboard gets. It is a different angle to the boat since the water is being turned by the centerboard.



I hope I am finding a better way to express my thoughts more betterer here, cuz I sho am not a very good instructionatoralist.