Lighting for 140 - MH and VHO

[Dazed And Confused]

I have a 140 gallon tank I'm setting up as a reef tank. Tank is 60"L x 18"W x 30"H. I know that a wider, shallower tank would have been a better choice, but fitment to an area was an issue in this situation. I already have a pair of Icecap 250W M/H ballasts and a pair of Ushio 10K bulbs along with an Icecap 660 electronic ballast for my URI Super Actinics. I have base and live rock mostly at the rear of the tank but I have about 2" between rock and back tank wall to allow for spray bar maintenance without having to take the rock down, etc. Most of the rock is at least 6" from the front of the tank with a couple of wide open "beach" areas . I plan to use a pair of Lumenarc minis (14.5" x 14.5" which leaves me 3.5") and want to use 2 actinic bubls on this setup. I can't for the life of me figure out why I should put an actinic bulb at the back of the tank other than for balance. How well would it work to push the MH's as far back as possible and run the pair of actinics up front? Looks to me like that would give me the best pop from the actinics and set the MH's closer to directly over the rock structure where the corals will be anyway. My other option is to put actinics at front and back and tilt both of them very slightly to point them toward the center of the bottom of the tank. How much light would I give up by not having them focused straight down at the surface of the water? These will all be mounted in a wide open hood that will conceal all but the very top of the LA minis. I'd sure appreciate any input or experience you care to share about a similar setup.