Lighting for a 12g, MH too much?

[sfsuphysics]

Sorry if this topic has been done to death, I'm new to this sub-forum.

I just picked up a cheap (literally and figuratively) 12g Nano-cube, just something I can mess around with before even considering shelling out bucks on a decent cube. I plan (or will try) to do a series of modifications to it to get more flow out of that little 500 lph pump (10x turnover is not enough IMO) and some other things.

However its the lighting that's bugging me. It comes stock with 2-18w PC bulbs, one of which doesn't work, but who cares they're going anyways. I was thinking of cramming maybe 4-24w(?) PC bulbs in there (just enough space it seems), with an electronic ballast that also is small enough to fit, Advance ballast you can pick up at HD that fires 32w T8 bulbs (plus I had one laying around collecting dust). However the idea of a small MH light bulb is also quite appealing, even if it uses those cheap ebay bulbs, it might be worth it.

The problem is I don't know much about small tanks and lighting. Will a 70w bulb be insufficient? Will a 150w be too much? And by "too much" I don't want to cook the tank or have to resort to fancy cooling devices (i.e. temp controller hooked to super fast fans to cool it down in a hurry etc).

While initially I thought I could take some polyps of zoas I have in my other tanks, I think I might also like to put a few SPS in there, cheap stuff probably, pocillipora, micropthalma, digitata, etc, i.e. nothing I'd cry about if I lost and I can make plenty of frags from my other tanks anyways.

So yeah long run on sentence aside, what direction should I go? PC bulbs? MH bulbs? if so what wattage?

Thanks