IOA early entry and maximizing both Harry Potter worlds

[HoosierFantasia]

Headed back to the darkside! We have a group of 14 and trying to be as efficient as possible. staying at HRH so will have express pass. My thought on maximizing the harry Potter worlds is to take advantage of early entry to IOA on Sunday and head straight for FJ. Do as much as we can there and then at 9am ride the train to Diageon Alley and explore there. Thinking if we are one of the first on the train we may be some of the first to arrive and beat some of the crowd at Diageon Alley.
we do have park hoppers and will be going back in the parks on Monday and Tuesday morning. So we aren't desperate to do it all on Sunday.
Does this seem like an efficient logical strategy? Anyone with more experience see a flaw in my thinking?

Bill

 

[macraven]

if you are going in july, both parks have early entry for hotel guests.