Nobody answered you, John. Perhaps in this thread, it's because the stock setup are continuous tubes from fuse exit to the former just behind the servo. I did both elev and rudd stock using those guides, and so far, so good. They center well, have good geometry of travel (considering the excess Ackerman that is built in and SHOULD be corrected).

I'll tell you my technique on OTHER airplanes, though. And this isn't sarcastic.
Carve/cut as needed I try to use a straight edge looking down from the top of the fuse, holding it from control takeoff to servo arm hole. Eyeballing, I put a horizontal hash mark roughly where the hole will be. Then I do the same thing on the fuse SIDE, and mark where it intersects that original mark. Then, I make a slot, about 1/16" wide, far enough in front and behind that mark that there won't be any rubbing. Works for me.

There are a lot more scientific, analytical, and anal-retentive, obsessive compulsive schemes of arrival at the hole location. For me, I like the "guess, mark, cut, make it work" approach. Less time, less stress, more fun.
But not as pretty.