Over the past 2 days I've manufactured a 0.125" thick 6061 T6 bus that will gather the grounds from the Avionics, VPX/IBBS & service busses and an airframe ground. A M8 brass bolt will connect this to a 16sqmm cable (AWG5) that will travel to the main battery negative post. I'm waiting on hardware to complete this section of the build.