1.5 days at US/IOA in September??

[klacey1]

So we're going down to Orlando for 8 nights in September. We're currently booked for September 11-19th, with plans to travel to US midday on the 17th, check into RPR, and spend the rest of the day in the parks. I'm hoping for early entry into Diagon Alley on the 18th; we'll spend this full day in the parks, stay over at RPR, and then depart for home on the 19th. That would mean we'd spend half of Wednesday and all of Thursday in the parks. I'm not worried about the amount of time, more like the days of the week. Should I bump our trip back a day, making it September 10-18th, so we spend half of Tuesday and all of Wednesday in the park? Or should the crowds be relatively low this week that it won't matter?
We typically only spend one day in the parks during our trips, but with the addition of Diagon Alley, I thought 1.5 days would be better. I'm really going back and forth on which days would be better, as we really want to do all of Diagon Alley, as well as FJ and our other favorites in both parks.

 

[RMulieri]

At this point it is all guesswork..No one knows what Diagon alley is going to do to crowds at this point.How crowds were last year and what they have been in the past really wont apply here till it opens and we see what happens