actually, if he's using 100% soil, vermiculite wouldn't do anything but retain more water... so unless that's his intentions then i wouldnt advice adding vermiculite into the soil now
if you're using up 205 watts for CFLs, why don't you just get a 250 HPS? yield will be way better as the HPS has better light penetration and output. you'll have thicker heavier and denser buds for an extra 45 watts used