Following vans plans for a fwd mounted battery, I drilled a 7/16 hole with a unibit thru the stainless steel firewall next to the battery trey angle brace. Popped in a plastic snap bushing.
Wasnt quite sure how the wires were to go from the gear tower to the firewall so I called Vans for some reasurance. Just forward of the rt gear tower there is a lip for the baggage wall. I decided to drill there Too far outboard and the wires would stress around a sharp corner. Too far left, and then they rub on the brake line. I went in the middle. Drilled 3/4 hole. Why larger hole than fw? Because I got carried away! No harm done. Just snap in 3/4" snap bushing after deburing edge.
Routed the 6 or 7 wires forward and out the firewall.
I will later bundle wire together in spiral wrap and also install a fire shield. and fill with