Andre, Nice to hear from you, how's it going in Anchorage? I've considered using geometry before but at the time I had a plane with wing fillets and the sides are never perfectly straight. In addition the distances between the servo, fuse wall, control horn and fuse side are fairly small and difficult to measure exactly for use with the formula. However, I'll try applying the formula and see how close I can come to the true exit holes, it should be fun. Thanks for passing this on.

Derek, I think the caliper idea is good if the servo arm and control horns are equal distance apart such as the typical pull-pull elevator (and you happpen to have a big outside caliper ). However, in this case we're coming from a single center point, also in the case of pull-pull elevator you're also coming from a center point. I don't see how the caliper method would work in this case.

Keith B