Something that bright is way overkill for a tailight.. I have found that using contrasting colors on the back will get you the most attention..

I use a Superflash and a Nathan LED Snap Band..

Another good option is to run your standard Red Tailight and use an adventure light as your contrasting light, lots of colors to choose from as well as mounting options..

http://www.botachtactical.com/novlabguar.html