The reason I believed I made the mistake of trimming too much metal is two fold:
Firtsly, when trimming all the rudder stiffeners you get into the mindset of cut to the notch and smooth it out with the scotchbrite wheel on the grinder. As you can see in the second photo you have to leave a lot of the notch in order to get the required minimum edge distance.
Secondly, the drawings don't show you measurements to prevent this.
I note from a search in Google that I am not alone in making this mistake and maybe Vans' could review the design aspects.
