Ok, I've figured out Quetzacotl and now have a reliable team that can farm him in about 50'ish seconds per kill, very repeatable. I've farmed 4 copies of his magicite with this setup, so just need to do 4 more kills to be done with this fight. Once again, this only gets expert, so I miss those 40 crystals for mastery, but at this point I don't care, I'm done with him after those next 4 magicite are farmed.
Onion -- Entrust, Wrath -- pUSB
Elarra -- Ultra Cure, Shellga -- USB
Galuf -- Ironfist Earth, Gaia's Rush -- CSB
Bartz -- Blastspell Strike, Tremoring Quadstrike -- USB1, USB2
Wol -- Grand Charge, Stone Press -- no sb (+40% heavy RM)
Magicite: Earth guardian (main), Catastrophe, Midgardsormr, Gizamaluke, Evrae
Video:
Quetzacotl in 50 seconds
As I mentioned earlier, Galuf can't do stone press + chain duty and maintain perfect timing for both, so I brought in a relicless Wol to handle stone press instead. Wol was chosen simply because he has the highest speed of all the heavy 5 users, and there's no room to soulbreak anyway so relicless doesn't matter. With a unit dedicated to doing absolutely nothing except charge -> charge -> press I can knock quetz out of savage immediately every time he applies it, and that's a huge dps boost to never deal with that damage reduction.
Another key change was swapping Earth Guardian into the main magicite slot. The reason I required last stand in p3 was because of the imperil stacking. If you save Earth Guardian until just before P3, it clears your imperil before the next one applies, which means you never get two stacks. One stack of imperil is fine and doesn't OTK anyone, so last stand can be skipped, which means I was free to go with only one healer. That means I could fit Onion on the team so we got his crit buff from pUSB, though Onion still had to entrust a lot of gauge to Elarra for medica's, so it was kind of like 1.5 healers I guess.
I stopped bothering with Astra sources too and just dealt with the paralyze. It's actually not that bad since on the turn he paralyzes it's only single target damage, so the healer curing it isn't any big loss.
Bartz did his USB1 + USB2 combo, which is sick damage, especially when his USB2 finisher auto-casts for 99,999 "free" damage at the end. With Galuf no longer wasting his time with stone press stuff, he could focus more on dps with Earth Ironfist, so I guess that wasn't a total waste to craft/hone. I do wish I could have a refund on legend diving Tifa though. She's worthless with only USB2 on this fight because she goes through 16 hones before the boss is even at 40% health then she's entirely dead weight. She needs a BSB (which I don't have) so she can keep contributing after the USB2 drains her of hones. That, or enough DPS to finish the fight in 30'ish seconds, which I can't do.
What's the deal with these magicite fights and the mastery btw? Do we have to sub-30 to get the champion clear? I mean, 50 seconds isn't all that terrible I thought, but still only expert ranking. So annoying.... I hope next month's two magicite bosses are less of a headache.