Quick and dirty notes for non-speedrunners.

P1S:
Nothing special. Full uptime fight.
Holmgang big busters 1 and 4.

P2S:
-9s Prepull IR might be a gain.
However, it is possible to do a basic IC IR IC opener, and keep IR on cooldown while managing mechanics.
Yes, you can use IR before Limit Cut happens. You’ll get 2-3 IR FCs out.
If you only got two IR FCs out, the third one will stay ready until the boss is back again.

P3S:
Normal opener, or -29s into Rend. This is highly special tech though.
You can take all of the busters by rotating Thrill + Rampart / Vengeance, with Bloodwhetting.

P4S Phase One:
-9s IR into Eye opener if you’re going all the way to Enrage.
Normal opener if you have the DPS to push the fight down earlier.
Holmgang the busters, all the other cooldowns are free for auto-attacks.

P4S Phase Two:
Nothing special here.
Normal opener, nearly full uptime depending on your group’s strats.

P5S: You may skip Tomahawk and opt for an earlier IR. Keep IR rolling and get 3 FCs off before Devour. Save Primal Rend for after boss is targetable again.

P6S: Nothing special. Full uptime fight.

P7S: As with P5s, you may skip Tomahawk. Keep IR on cooldown. Fight lines up nicely with 2.45, as most of the knock-ups happen during GCD downtime.

P8S Phase One: Full uptime fight, apart from Dog 2 phase.

P8S Phase Two: Recommended 2.45 GCD. -11s IR opener, get IR FCs + Primal Rend off before HC1. Keep IR on cooldown for the most part. On HC2, wait for the adds tethers and then use IR, reopen with 3 FCs. Nearly full uptime fight.