If all I wanted was a reliable way to get power to the back, I would stick with my current setup of BuM two conductor wire and clear Gorilla repair tape. The tape does get ugly after a while, even when I use latex gloves to put it on. I have also used the coax Supernova wire, it's a bit nicer. I bought some of the frame plugs for Di2 wires, so internal routing with a loop of wire at the headset is also something I have considered. I would like to have a loop for attaching the wire inside the bb shell.