Pick what you want, what fits your room better, what your more comfortable with cause no one will agree. I have both, 4x600 and 2x1000, and I will not ever use a light rail, we aren't or at least I'm not mimicking the out doors, I'm improving on it and I see better results without but that's just me. I've been to some of the biggest greenhouses in the US and I have always seen a stationary lights 95% of the time unless there was a unique situation such as propagation on mums. So your call.