You should listen to Len Testa interview from one of the Dis unplugged pod cast in early March. Very interesting information. There is a lot of statistics that goes into the crowd calendars, but he noted that from some of their research they have noticed that when there are lower crowds that the capacity of rides is also lowered thus less staff - saving the park money. So you could be going at a lower crowd time say a 3 or 4, but your wait times could still be similar to a 7. You best tactic is to expect heavy crowds, plan your day with that in mind, use your FP wisely to allow for 4th and 5th FP. Going at late September should be better crowds compared to most times of the year. So there will be people there, rides will not be walk on, you better snag your TS ADR (or should have done that already), Use the
MDE app to check wait times so that you are not walking up to splash MT to find a 60 minute wait. The app will help you hit those rides with lower waits and save you time from running all over the park.
