You can use BotD again at the end of phase 1 in Thordan and still have it back for the Knights. In this way, you get 4 gsk in the opening phase while maintaining the higher dps brought by using Phlebotomize. C: Dropping Phleb in single-target is actually an overall dps loss, even with the gain of +1 gsk.
I'm not a super good authority on A1S. I know the fight pretty well, but I do a lot of wonky things that aren't exactly optimal.
There is something to be said for holding DFD for the first add spawn, rather than using it in the opener (I always forget to...). You'll get 3 hits of DFD in phase 1, 1 hit in Phase 2, 1 hit in Phase 3. If you use it in the opener, you get 2 hits in Phase 1, 1 hit in Phase 2, 1 hit in Phase 3. It comes down to B4B overlap, and I'm not totally qualified to calculate that. The first DFD in p1 gets B4B (and crit buffs) while the second one gets to hit an Alarum and the Oppressor which would be ~4.35-4.4x DFD. Holding it for the first Alarums is ~4.14-4.25x, since they have a ~25-30% buff on damage done to them. So if you're using it on Alarum+Opp for the second shot, it's better to use it on cooldown. And if you only get 1/2 of the Alarums from the first DFD (since you have to wait for the SMN or SCH to pick them up first), you lose a significant amount of dps, since then you have exactly what the second DFD is in the first case, just without the additional B4B one at the start.
But uh, imo, there's two ways to handle Alarums.
In this kill, I handled them in way 1:
1. Pick up the add with ID the first time into Dis>CT on the Opp, before returning to finish the Alarum off.
--- Second one comes up just after FT, so pick it up with 4th>HT>ID>gsk>[Dis+CT on Opp]>back to Alarum to finish.
2. Grab the Alarum and murder it before the lasers come out with a series of quick hits incorporating off-gcd skills. Remember it has a ~1.3x bonus from damage on it, so saving a Jump or SSD from the opener to hit the Alarum isn't a significant loss of dps, since you'll still get the same amount in the ~90s phase.
Those are the only real tips I have re: A1S, since I myself am not doing it optimally, and I don't really have any answers on how to do it better. It's hard, because most good players have done 0-jump kills, now, and those aren't really super helpful in terms of how to effectively do the fight, since they're all bumped up by Astrologians and short kill times, so it's hard to reason out which one did it the best compared to which one just got the luckiest crits.