Hi,
I think that maybe they should do a sticky on the "watts/gallon" rule. I think that just like the "inch of fish/gallon" rule, it is very bad advice to hand out to beginers.
The other day I read a post here about someone saying how his need of light was decreased because he had a 15g tank filled with live rock and substrate so that his real volume was less. Some friend or someone told him that, naturally, he needed less light (watts).
That is really bogus.
Anyway, IME NO lights are not good for corals. Mushroom can survive (not thrive really) on NO lights.
I am glad you reconsidered and now are going with PC. It is a better choice and if you upgrade your tank, the PC system can be use as part of your next system.
Good luck.