I'm certain I'm not the first to think of this, but I read a lot before my trip and I never saw this tip.
This evening I returned to HS for a 7:30 Fantasmic. It was 6:30, so I decided to hop in line for TSMM. It moved fast! There were very few FP+ riders at that point. Posted time was 50 minutes, I set my phone timer and was on in just under thirty minutes.
TL;DR: if you hop in line about thirty minutes before the park closes the line moves more rapidly as there aren't as many fast passers.
This evening I returned to HS for a 7:30 Fantasmic. It was 6:30, so I decided to hop in line for TSMM. It moved fast! There were very few FP+ riders at that point. Posted time was 50 minutes, I set my phone timer and was on in just under thirty minutes.
TL;DR: if you hop in line about thirty minutes before the park closes the line moves more rapidly as there aren't as many fast passers.