With a shorter 8-32 screw that I scavenged from a spare terminal post, I had the necessary hardware to finish off the pitch servo wiring ground. But before finalizing the wiring there, I decided to do a quick wrap of the self-sealing tape around the wire bundle going into the d-sub connector.Then I reassembled the backshell clamp and secured the airframe ground with the screw.
Next, I determined I would use the 4 AWG welding wire to re-make the short runs from the battery to the battery contactor (positive) and the battery to the ground (negative). I needed some shrink tubing to close out the ends and insulate the connectors, so I ran to Ace Hardware and grabbed a package; then, it was a matter of crimping the terminals on and shrinking the tubing.
Now I need to make the adapter for the battery tray to secure the battery.