In small grows those dual reflectors work wonders but in your huge area isn't that a waste? When growing in an area your size I've always noticed it to work better to alternate HPS then MH in separate reflectors to get a wider range of output. It'll be cool to see how they work for you.
this is for phxfirs as well,
we use the dual bulb reflectors so we can,
#1- increase the overall lumen output from a single reflector unit. This helps with penetration capabilities of the reflector as well as foot print clarity. Meaning, less loss of spectrum than if we were to run alternating MH and HPS lights. If you have a five foot floor pattern from a single light, move another light in next to it to give yourself another five foot floor pattern, you have a 5 foot by ten foot pattern. Unless you over lap the two light foot prints where the secondary light zone starts to create a third primary source to offset the photo-tropism effect of having the two lights farther apart.
#2- increase the overall spectrum output of a single reflector, rather than run 2 HPS or 2 MH we run one of each. Photosynthesis doesn't work on just one spectrum so using one or the other is never as good as using both.
#3- decreasing the heat in the environment as well as the costs to do so by using a single dual bulb reflector. Much easier to vent one light than two
#4- yield, the holy grail of grower BS'ing. To increase yield. We super crop to the 33* around here and the secondary light zones are well used.
Every situation is a little different than the next. Even the buildings we utilize act differently during the different seasons. It usually takes us a bout a year or so to get the building itself dialed in on a grow this size.