There are many screw holes to chose from. Giving you my clock angles may not apply to your specific installation location. I installed my push pull rod and made the length only long enough as necessary. You can adjust the length with the rod end bearings but when all said and done when you put the flight control through its travel for the respective servo it can not cause the arm of the servo to go directly in line with the rod. Once I kinda figured that out I installed the guard at the angle that prevented it from "over throwing". I adjusted the rod end bearing length from there so that the arm doesn't even hit the stop.
One more thing. I had to make an entire new aluminum rod and reset the stop after I found that when rigging the Flapperons, It throws off everything with regard to the aileron control. I would advise that you fabricate that part after rigging. Probably too late for that but thought I might add that in for those who follow.