I'm doing my first ever grow too. I've reached the end of the main veg growth stage now. I just used some normal soil. All seeds grews very fast and well. I never used any artificial light until there were a few leaves. Although I did have them on my windowsill where daylight could reach them. I'm thinking that it would be a good idea to have just one light on at the moment at some height. Then when you can see they're coping well go for it with the lights! As for the soil you're using it should not be too much of a problem if the roots have enough soil to find their way in. Make sure they're not just sitting on lumps though.

Hope this is of some help.