I do recommend the heavy duty wheels for the mover and trolley. I only got a grow each out of the stock wheels with these heavy reflectors.
Also I use the Sun Systems eEqualizer hot spot diffusers to help get the lights closer.
At 2400 watts the movers get the Light down into the canopy.
I had ran all 4 HPS before but definitely get better results with 2 HPS and 2 MH combo.