I reattached the right aileron for what I hope is the last time this morning. Once I had it attached, I installed the counterweights on the balance bar and attached the ailerong pushrod (which runs from the bellcrank) to the horn on the aileron. Time to test the aileron deflection.
The aileron deflection was off by almost 8 degrees in upward movement! I guess that's why Zenith has you install a threaded pushrod where the rod end can be adjusted. Luckily I also hade ample extra pushrod available for unthreading the rod end. All told, it took about 8 threads-worth of extension to get the up and down deflections right on the specification in the plans (11.5 degrees +/- 1 degree.
Aileron mounted in position, riveted in place, and fit to the wingtip.