Tonight I finished riveting the hinge brackets to the rear spar assembly. That pretty much completes the riveting on the rear spar. I need to install the HS-411PP assembly by using nuts/bolts and properly torquing those. I bought a nice torque wrench a while back at Sears, so shouldn't be too much of a deal.
After that, we move on with riveting the skeleton/skins of the horizontal stab.