For those of you wondering about the wiring I posted a DIY specifically for it. It's set up to have a full off switch killing all light, a full on switch to manually light the fog, and a second on position to allow solid light with brakes and blinking with reverse.
DIY: Rear Fog Light - Flashing Reverse - Solid Brake - Full Override
Simota1, hope you don't mind me branching this off as my DIY is specifically for a certain wiring type and I didn't want to clutter the thread.