There's a number of threads about this -- one forum is all about using My Magic Plus, FastPass and Tiers, etc. 
Here is also a link to N&R about the new tier system at DHS.  Maybe this thread and the forum listed above might be helpful.  I can't speak to any of this, because I haven't been to WDW since last year.  It sounds fairly complicated and doesn't seem to allow for as many fastpasses to the major attractions as before.  I wish they would have just left the older FastPass system in place, or just eliminated the entire fastpass concept entirely.  The whole thing seems to stress out a lot of guests, so you're not alone.
	
	
		
			
			
				
				Short Story:  On August 29, Tower of Terror and Rock 'n' Rollercoaster will be added to Toy Story Mania, Slinky Dog Dash and Alien Swirling Saucers as Tier 1 Fastpass+ selections.  Star Tours stays a Tier 2.  Smuggler's Run still set to open as a non-FP ride.  I am unaware of any other changes...
				
					
						
							 
						
					
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