John runs those reflectors on his 600 which is 48 wide and imo, there is not enough light on the edges for SPS. The center channel is fine, but then it just fades toward the edges. In fact, he is getting ready to add some T5's for extra light. Saying that, it all depnds on how you are planning the VHO's. You are probably asking the wrong guy as I like lights.
Karl's tank was 36x36 and he even had light issues near the edges and that was one reason why he eventually went to 2-250's and then back and forth.