I added third brake lights to both my 38 and 53. For the 38 I found a universal STOP light and put it on a stand to clear the bottom of the back glass with the brightest 6v bulb I could find. For the 53 I used an implement light that had a clear lens. I used stained glass paint to turn the lens red and used the 12v equivalent bulb of the one I used on the 38. Quite noticeable. I couldn't find a picture of the 38's light illuminated but you can see it below.
Save a life, adopt a senior shelter pet. The three main causes of blindness: Cataracts, Politics, Religion. Name your dog Naked so you can walk Naked in the park.