actually I have every single Halftrack manual from base shop data to all the 2700s, and not a single one of them says anything about
going from the battery box to the J-box, no wire size no conduit type nothing. just a vague drawing in the schematic.
and having gone through every picture posted on the interwebs, Ive decided to just go with a Pair of #4 welding wire, in 3/4 flex to the first box
hopefully that's enough to run both radios. on the crossover Ill use two number 6 in 3/4 flex.
I wont try to do the bonding to frame, to much room for error. a direct ground back to the battery is way more secure
BB