I would keep the MH for the first two weeks instead of just one. The most stretching occurs within the first two weeks and MH helps keep the plants from stretching. at least thats my experience. My plants that i'm growing right now grew from 18in to 36in in two weeks. I'm about half way through my third week at this point and they are about 38in tall. They are starting to slow down now and will probably stop growing height wise around the end of the 4th week. Stretching will help your canopy spread out so dont worry about that. You definitely don't want to start trimming off fan leaves because the plant uses those for photosynthesis. Lower canopy penetration is a problem you always have with multiple plants under a low wattage light in a small area.