I manufactured the rudder stops P/N: F-792 as per the Van's drawing 27A. However, when I checked the rudder maximum deflection I found there was at least 5/32 inch gap between the rudder stop and P/N: R-405 on the rudder.
I then redesigned new rudder stops out of the same material using Van's dimensions for the vertical face (i.e. that sits against the fuselage) but modified the horizontal surface to achieve the correct rudder deflection.
The reason I used the original Van's dimensions on the vertical face is the rudder comes in close proximity to the fuselage skin at full deflection. If you extend the length of the stop beyond the skin it may contact the rudder and damage the skin.
I have included a drawing showing the finished dimensions of my new rudder stops (click on the link below to view). I would suggest that you mark out the horizontal surface but then add at least 1/16 inch extra material on the face that contacts with R-405. This will allow you to 1. remove the required material to obtain the stated rudder deflection (i.e. 1 & 1/8 inch gap from rudder skin to elevator trailing edge) and 2. shape the rudder stop so that the entire surface will contact R-405 instead of a point.
My other piece of advice is to do all of the above before riveting the rudder stops on (i.e. easier than having to drill out rivets if you make a mistake).
I hope this information is helpful. The second link below is a photo of my installed left hand stop.