Installed the outboard seatbelt attach points. These are 1/8th-inch-thick aluminum extrusions that arrive from the factory in a just-from-the-forge state requiring a bit of fabrication to fit the plans. First, I hacked off the corners on the face of each extrusion (literally hacked - with a hacksaw!) and filed them down to the final 15mm radius required by the plans. Next, I drilled out the bolt hole on the face of each attach point where the seatbelts will connect. Finally, I fit each attach point to the left/right gear uprights (hefty aluminum extrusions in their own right), drilled them out, and bolted them in place.
Out-of-the-crate on the right- finished on the left.
Right seat from the inboard side. Seatbelt attachment is on the far side.
Close up of the finished/installed right outboard seatbelt attachment on the aft gear upright.