How big is the tank going to be? A pair of true percula clownfish in a 10 gal. is a bit of a no-go if you ask me. Their disproportional bio-load could have adverse side effects.
As for the question at hand. Normal output (NO) lighting is fine. I would probably invest in a 80Watts+ hood however just because it's fun to watch clownfish host around frogspawn or torch coral, and those can easily be kept under 80Watts+ .
