As a 1/16H 16/16N raider we decided we first wanted to clear ToES before starting heroics. The reason is that ToES gives so much good loot, and also tieritems and experience, that the first 1-2 heroics should be easy. Within an hour after killing Sha we also killed Heroic stone guards. Now, about 1 to 1.5 hours of practice on Feng has brought us the insight that he is very easy if we can learn the shieldphase or burn it down,
What we currently do: Kill ToES for the gear, then run to MSV and practice there. As a 3x 2.5 hours raiding guild we can clear terrace in just over an hour if everyone is focussed, so we have 6.5 hours to progress heroics. I suspect we kill Stone guards and Feng on heroic this week, then we will see next week.