The Fury of the Five Flights trinket could use a bit of a tweak. I'm at 0.91 shots per second, according to the spreadsheet, which means it takes a bit over 18 seconds to get a full stack. Not bad, but not trivial in my opinion.
Since you are already setting the duration of the fight, you could use this to get a more accurate number.
16*AvgShotTime/TotalTime + 32*AvgShotTime/TotalTime + ... + 304*AvgShotTime/Time + 320*(TotalTime-AvgShotTime*20)/TotalTime
=3040*AvgShotTime/TotalTime + 320*(TotalTime-AvgShotTime*20)/TotalTime
This number approaches 320 as TotalTime approaches infinity. With my frequency this puts it at about 311 AP for a 6 minute fight, but only 294 for a 2 minute fight.
Obviously this trinket would still have its caveats, but we could use this to figure out how long a boss fight would need to be (or a phase change before we must lose stacks - Mimiron?) for this trinket to be better than say Bandit's or Mirror.