Transplanting?

I am goint to buy 30 clones that will be in little rockwool cubes. I have 4 1000 wats lights that I will be running metal halide bulbs in for the veg. I also have 60 3 gallon pots. I am going to veg with 15 3 gallon pots under each 1000 watt metal halide. Will this be OK? Should I start the proces in the rockwool cube with lights up realy high then once the roots start to show put them directly into the 3 gallon pots? My friend is telling me to start with rock wool cubes, then use 2 liter bottles, then transplant that into the 3 gallon pots. I really dont want to put the plant through any kind of transplant shock.