No experience with MH or with a tank near that size. What are the dimensions? Is it 72" wide? If so, the 3' 96w CFs would fit over it nicely. Using four of them would give you 2+ WPG, which, IMO, would be find for this project. But, since you have the MH, and since the tank is likely a bit deeper, using those gets you over 3+ WPG, so they might be the better option.
Personally, I would go with all of them on at any one time. In larger tanks, the WPG rule starts to break down, so getting much above 3-4 WPG is asking for a pretty delicate balance, and that might not be the best place for you to start with your first planted tank. Perhaps you could use the 2+ WPG CF for 3 hours, then the 3+ WPG MH for 4 hours (for a mid-day light boost) and then finish the day with 3 hours of CF. But that seems more complicated than it might be worth. I'd guess the MHs, raised slightly as suggested earlier to try to reduce dark corners should suit you fine.
But, again, these are my gut feels,