I was wondering about this as well--have you ever not been able to get into Fantasmic? Should 45 min always be enough time if going standby? I am going on a CL 6 day in October.
45 min. is a good rule-of-thumb.
It would be a very busy day that saw 45 min. NOT get a guest into the show.
And, a day-of 4th or 5th FP+ for Fantasmic! will give a guest an extra amount of choice,
as the FP+ sections make up virtually HALF of the entire number of seats, total.
But, it CAN happen.
60 min. before will be about the earliest anybody EVER needs to arrive, and most nights that
will get the choice of nearly any position available.
Couple that with a day-of FP and you'd be "golden."
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 Package 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.)