Used 6AWG for wiring main electrical connection from 2nd ANL fuse on firewall to VPX primary power connection. Installed lugs in proper clock position and added a firewall doubler/nutplate for securing both the primary battery positive cable and the primary VPX bus feed. Nothings going to move. Its tight. Added more adel clamps just prior to the VPX wire going through firewall, and then once inside, added another adel/nutplate to the bottom of the right sub panel to firewall rib. That holds the VPX connection excellently.
There's the main positive battery cable and the VPX cable secured to firewall and engine mount.
063 doubler behind the firewall for a 10/32 bolt to hold those big cables snuggly.
VPX bus feed secured just prior to passing through firewall.