as for the light......go with a couple of 42 watt compact florescent lights, they will be perfect for starting seedlings and getting them ready for your 600watter.

....as for your taproot situation its hard to say without actually seeing it....but if it was a tiny portion there might be a chance at survival. Keep in mind its the very first root system this plant has at surviving and any stress to it is going to delay and possibly kill the process.
Who did you get your fimmed seeds from?