Match Drilling and Reaming Elevator Horns

Earlier in the build, the elevators were fitting to the horizon stabilizer and the center hinge bolt was installed,  now it was time to match drill and ream the elevator horns.  This qualifies for the "noteworthy" list because it is unforgiving: if the holes in each arm are not perfectly in-line and perpendicular, the stabilizers will be out of plane when the horns are attached to the pitch control rod-end.
Left and right elevators were attached to the stabilizer and the counterweight arms clamped to the stabilizer,  but a quick check with a digital level indicated the need for some shimming between the clamps and the L/H counterweight arm.

A couple of blocks of sufficient thickness to fit snug between the arms was made and a pilot hole was drilled thru it using a drill press to ensure alignment of the  holes in the arms.  Given the difficulty of drilling weldments from Van's (that's a good thing) , I gradually increased the alignment holes until they were big enough to ream to 3/16 diameter. The bolt was installed and the arms were clamped to reveal perfect alignment of the left and right halves of the elevator. 
Angle measurement of the horizontal stab:

is the same as the angle measurement of the match-drilled elevators:

As added assurance  that the two elevators were in plane, a 4 foot level was centered between the elevator arms and an equal distance between the lower edge of the level and the elevator surface at each end of the level was verified.
L/H side:

R/H side:

Final match drilled elevator horns: