when I added a simple cable from a battery to the buss bar it all made more orderly sense. sure cleaned the system up and,,,,, easily done. Don't know your system but you said it's a 2 bank system so you need to get all those extra lines to work from either bank. I'm not sure but I think it would mandate that the buss bar would need to be after the selector switch so it would draw from the selected bank keeping the offline bank from having an electrical draw. We have a single bank system with a separate start battery circuit making it easier as there is no selector switch. (better for cruising)

Instead of a buss bar you could even take those wires and put in a sub panel.

Having said all of that, don't forget, I'm the guy who said your battery was toast and needed to be replaced. I also dyslexed single & double braid line.