My solution for mounting the rear super nova light. Since I'm required by law to have a red rear reflector, and the e3 rear tail light doesn't double as a reflector, I simply drilled a hole in the reflector and used some epoxy. This way the mounting hardware for the reflector is all that is needed. I prefer the large reflectors you get in auto parts stores, they are much brighter than anything sold for bicycles.

I use the Spernova E3 triple which is very bright but expensive. To mitigate the blinding effect of this light on other road users I constructed a light shield. The shield has the added benefit of improving the beam pattern. I have mine set to be easily removed because I use it on different bikes but this does allow me to bring it with me instead of leaving it on the bike.