wow...that is good to hear.

What is the temperature at the top of the canopy? That will tell you just how close you can get the light with out burning the tops of the plants.

There is a point late in the cycle where the leaf will thin out because the plant is using up the stored energy of the leaf. At that point the leaf will show bad nut burn and be crisp but browner then yellow and the tips will be more white and burnt from the heat of the light.

Just watch the canopy temperature.