With the mods the 6ga set would fail at the cable that has highest load, I dont know what one that is?
Maybe you can double up or even triple the 6ga wires on the one connection, I bet that would help till you find a replacement
I have read many time 6ga is just enough to get by with stock carts playing golf.
After a long trip fully loaded and stock i had a few warm connections now if I was cought on a log or turning around on a big hill it would probably burn one up.