Adding a brass(?) contact plate to a flashlight

I have a Small Sun ZY-T08 that I’ve done a bit of modification to (wired up a 7135x8 Convoy driver to the stock board, swapped the emitter) and I love it. I have noticed though that the gold plating where the positive ends of the cells contact the driver is showing signs of wear. How would I go about solving this problem? Would it be difficult to install a brass contact ring like in the Q8? I know people have done that to this flashlight before, but I’ve never soldered something so large before, and I have no idea how I’d go about that. Does anyone have a tutorial?