Few year ago I had worked for a propane company that was owned by a true 'Rocket Scientist' . The owner worked with NASA after one of the Titans shelled apart just after it left the launce pad. (maybe you remember the news clips of a huge fire ball?) That rocket exploded due to electrical grounds. This is going some where,,,,,
Working as Maintance Manager on his trucks, everything he had ran on propane, and everything was computerized to monitor the propane it burnt, cool stuff! But if the grounds and wires were not heavy enough there were problems, dirty electric Robert called it.
Working with ol-Robert, it did not take long to learn how to wire his equipment, if you read the chart for wire gauge requirements, and doubled it, you were on his team. Especially if you added extra ground-wires.
To this day everything I run has quicker battery recovery, brighter lights and more constant electrical operations just by running heaver wire then it came with. It is really nice to have hi-beam lighting on low-beam and killer hi-beams, or heater motors that push you back in the seat. (well that might be a stretch)
Moral of the story, wires and grounds can never be to thick.