If you want a shield get a jimbo shield. They are great and low profile.
What are you trying to accomplish with the lights? Are you changing it for looks? Or are you looking for more light?
If you are looking for more light LED's will be the way to go on a TW. Its electrical system is not setup for running a lot of extra electronics and LED's draw a lot less power and give off a ton of light.
I have the Solstace LED's in the euro pattern that Pro cycle sells and they are fantastic. I have mine mounted up on the forks using some small brackets that PC also sells. The have stood up to a ton of offroad abuse.
Here is what they looks like installed on the bike.