It was reported here a few days ago that somebody watched fireworks from the carousel near PFH and went into the meet and greet right after it was over and had great luck that way.
I hear so many people say go at rope drop, but the reports you hear from the blogs are that that tends to be the worst time of day to go.
First, I'd try after the morning rush but before crowds get huge, say 10AM. If it's still too busy, I'd try afternoon when all the late arrival crowd are getting food and all the commandos are in the middle of park hopping, say 4-5. Then, if still too busy, I'd try right after fireworks. I wouldn't depend on the late strategy, and I'd ask the CM at PFH when they plan on closing down the line.
One game changer. They recently tested something similar to legacy fastpasses for the standby line where they gave out return passes for the standby line (referred to here as SB+). Keep reading here. IF they go to return passes for standby, then the best strategy will be going at rope drop and securing a return pass.