To me the choice would be based on the corals, the 6095 is a more broad gentle flow so it is best suited to LPS and softies, the 6055 is more forceful and the flow covers a longer area making it better for SPS and longer tanks. My personal opinion is that ideally flow can reach the far side of the tank from the pump so that their is some bounce back and a circular current. I would also consider the 6105 for that reason. A pair of 6095 will cover the tank, but the flow of each pump will only span just past the middle of the tank. The 6055 will also not quite reach the far end. I could see starting with 2 6095's and adding a pair of 6055's if the tank is more SPS intensive. I could also see 4 6055 or 4 6095 aimed from back to front to get a bounce back and circular current going which will more effectively sweep up debris. You could also use 2 6105's, one on either end, though you would not likely ever use the at full power unless it became a full blown SPS tank.