Which node is the most efficient for seals to exchange for QP in this event?
It really depends on your available servants & the CEs.
I would go with the Tohsaka Residence Rank EX mission (or Rank A if you have problem clearing Rank EX) if you have Lancelot + His Rightful Place MLB or a 5* CE from the gacha.
CEs aren't a problem, and I do have Lancelot. I don't remember much of the quest but though I have no trouble clearing it, it's not as fast as I'd like, so I might try Rank A if I take too many turns farming EX.
I would recommend the Samurai Residence node EX if you have Hassan of the Hundred Personas, Emiya(Assassin) and Hassan of the Cursed Arm for that sweet bonus.
The node is easy to farm and you get a ton of seals. The last wave involves a Shadow Alexander(Rider) and a Chimera(Berserker).
I've been farming the Bridge Battle EX quest and averaging 1.75 million QP per run. I'm hunting Forbidden Pages and strangely enough I've got more drops from the Bridge quest than the Academy EX quest. Team of Santa Alter, Shiki, Hassan, Alexander, and my new 0 Star Avenger, all using His Rightful Place CE.
