Q: I don't have the Saint and Seducer mythic, what else can I use?
Great alternatives would be Monomyth Reforged (perhaps run 5-6L if doing so), Ring of the Wild Hunt (if you enjoy being supersonic fast) or Markyn (for some extra flat wep/spell damage).
Q: Why do we run 4x pieces of rushing agony on the front bar?
I choose to run an extra piece of rushing agony for the extra penetration (4th line bonus). Alternatively, we can swap this out for a trainee chest (and run 3x pieces of rushing agony on the front bar) if we'd like a bit more health and armour.
Q: What options can we consider if we wanted additional health/armour?
We can run a trainee chest on the front bar, swap our armour glyphs to tristats (prismatic defence), and swap out one of our flex skills for spiked armour (for major resolve). This should give us around 35k hp.
Q: What other skills can we add to the rotation if we wanted additional sources of damage?
This setup is intended to be flexible, so you can add/swap out skills depending on your preferred playstyle. Additional skills that complement well include proxy det or even activating contingency before going in for the lotus fan/pull for the extra damage.