Used a fly cutter to cut the hole in the panel for the eventual MGL radio.
Re-made the ground wires for the upper and lower mags. When looking at a photo of another AeroVee installation I saw they used a Faston tab (1/4") to attach to the studs of the upper and lower mags, to ground them (photo #2).
With the major work of the firewall done, I put the engine mount back in place. Photo #3 shows the end result.
