Made a new shim to go between the rudder horn and spar. The plans and instructions call out a shim that's 1/2 wide which has three holes in to match the three holes at the bottom of the spar common to the control horn and reinforcement plate. I made one per the plans and used it while building up the rudder sub-structure but when match drilling the holes through the reinforcement plate, spar, shim and rudder horn I discovered (after drilling) that there were two additional holes in the reinforcement plate that came with my kit than was shown on the plans. I assume Van’s added two additional rivets in that location for added strength so there’s really no problem except there was no shim where those two holes were so the clamping force from the two rivets would distort the spar web. The answer was to make a larger shim that would extend higher on the spar and cover those two holes in addition to the three at the bottom. Fortunately there was enough aluminum stock left of the right thickness so I made up a new shim and matched drilled it to the holes in the web. I spent the rest of the build session replacing eight rivets in the VS rear spar that had non-concentric shop heads from holding the pneumatic rivet squeezer on a slant.
Original shim and replacement
Rudder spar, reinforcement plate, shim and rudder horn