That is a great install. And it is the unit I really want. Things are already set up in close to a way that would allow all battery current on the negative side to go through a single location - obviously where I'd put the shunt.
My debate is a simple voltage gauge vs something very similar to your install....time will tell who wins
Right now, weekending, I'm not sure I need to account for every amp in and out - but boy I'd love to have it!