I might be wrong, but I think the Light Sensor and Rain Sensor are in the same unit in the rear view mirror connected to the windscreen - so I dont think you'll be able to "gaffer tape it", otherwise the auto wipers wont work.

There is an option in MMI to turn DRL on (daytime running lights).

I think if you want dipped beam headlights on all the time then you need to code that with VCDS - there was talk of it being possible by changing the country code.