Digita's are pretty easy SPS. Get a frag and give it a try. I would keep it as high up as you can. I have mine about 6" directly below a MH bulb, so I can't really say how they will do with pc lighting.
On a side note, I believe UVL either has out now or will be coming out soon with a pc bulb with a built in reflector in it like their VHO bulbs. They are supposed to be a big improvement for pc bulbs.
I just checked UVL's site.
Here you go.