Self-steering

This is a link to free windvane self-steering plans.

http://www.mindspring.com/~waltmur/Self-Steering/
 
Anybody have any thoughts, I am on the edge of giving it a try on my 27' plastic sailboat (now that I have read both Oughtred and Hill's glued lapstrake books my thoughts have wandered away from Supermouse)
Justin Meddock