My ADR date is Tuesday, March 31st as well. So I was wondering the same thing. My original plan has us going to HS on Friday, but I want to change that if there are EMH at that park that day. And I want to book a Fantasmic dining package, as we have never seen Fantasmic before.
Just to let you know… you can have virtually the same experience at F! (without buying the meal) by just booking a day-of FP+ (maybe your 4th or 5th FP+ of the day) and just arriving at the F! theater between 45-60 minutes before show time.
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What that FP+ will do for you is to allow you to have access to much more of the theater.
(That way you could choose to either sit in the FP+ section, OR in the Standby (Walk-up) section, whichever offers the better seats at the time of your arrival.)
Map Below-
Arrows indicate the center of the seating.
Shaded areas:
(First or Only F! performance of the evening)
Cyan= Standby (walk-in) seating
Red= Dining Plan Reserved
Blue= FP+ Reserved
Purple= Can be either FP+ or Dining Plan Reserved, depending on needs.
(Second or Third F! performance of the evening)
Cyan= Standby (walk-in) seating
Red, Purple, Blue= FP+ Reserved
(Although much of the outer Blue will likely be used for Standby.)