Finally mastered!
First off, the team I used in my first two "Expert" runs:
Auron: Buster Sword (CC), Edin's Coat, Godo's Mask, R4 Draw Fire, R5 Retaliate, Dragoon's Determination
-Auron has Dragon Fang SB
Red XIII: Grand Glove, Holiday Mittens, Vossler's Gauntlets, R4 Magic Breakdown, R2 Full Break, Freedom's Wish (probably should have used Self Sacrifice but it didn't really make a difference)
Tyro: Golden Sword+, Fire Armlet, Wolf's Earrings, R3 Fire Blossom, R4 Lifesiphon, Dr. Mog's Teachings
-He has Sentinel Grimoire
Yuna: Lullaby Rod, Crystal Armlet++, 4* Mind Boosting Accessory, R2 Shellga, R4 Curaja, Mako's Might
-she has Hymn of the Fayth
Terra: Maduin's Horn, Edin's Coat, Terra's Pendant, R4 Ruinga, R2 Meteor, Devotion
-She has Magitek Missile (duh?), and Trance Flood
RW: Fenrir Drive
Notably, Terra would save her Soul Break for the 2nd and 4th charging phases because it's 16k damage, Red XIII would drop the Roaming Warrior since he was basically the only physical fighter worth a damn who was on strict offensive duty. Auron mostly existed to take care of all the ST physicals this fight had, which was a big help, though the occasional Dragon Fang both hindered BS' (...how fitting an abbreviation that is for the fight...) MT physicals, while doing about 8k~ to all enemies. Red XIII would also occasionally drop the Holiday Mittens SB to increase his, Auron and Tyro's damage. Ultimately, though, I couldn't beat him fast enough.
So Red XIII was the weak link I feel. Everyone else was playing too much a key role. Yuna is the white mage, and has Medica SB, that goes without saying. Terra was my primary AoE Source and has an occasional ST nuke when necessary. Auron was stopping a lot of damage, and doing a fair amount of his own between his counters, and had a big MT damage attack that could be used on occasion. Tyro has Sentinel Grimoire, and between Fire Armlet and Fire Blossom, his MT damage was actually pretty respectable to the Shadow Creepers (about 5k to them) so naturally I look for more options. Faris comes to mind thanks to her Soul Break but she's stuck at level 65 at best, and considering Red XIII I egg'd up quite a bit ABOVE 65, and has Synergy, I doubt Faris will make a difference even with the MT Soul Break. So I move on from Supports and just look at shear DPS.
First I look at Zack. Synergy, good stats, and I have Rush Assault...but he's also stuck at level 65 and while with Synergy that'd help, again, he's being compared to someone somewhat higher who also has synergy, so don't think that'll work. Squall and Lightning can both hit 80 and have Soul Breaks too, but again, Red XIII with Synergy probably beats them. Tidus has a Soul Break too, MT one at that, but again, same problem, and if I can't justify Squall or Lightning, I struggle to justify Tidus.
So...I go with Garnet first thinking maybe another source of MT damage will work. I hone Ifrit to R5, hone Valefor to R3, 8 shots should be enough alongside Terra, and she has her Ramuh Soul Break on top of that! I give her Devotion, because she needs it more, hand Terra Blood of Espers. Ok, let's see how this works!
...it doesn't. Garnet's not doing enough, Terra's Soul Break damage suffers from lack of Devotion, and yeah basically it's a was.
Then it occurs to me "Why not just go with Cloud?", who has all of Red XIII's advantages, and I can give him Pound and Armor Break because DPS moves as I feel my mitigation is just good enough between Shellga and Sentinel Grimoire (the MT physical hurts but is manage-able with SG, so it's really the magic damage. Again, a large part of the physical damage is covered by Drawtaliate.) I can have him swap with Tyro so he gets a good weapon (Tyro's damage suffers a bit but honestly Tyro's damage as the least meaningful, at least on ST. His MT damage suffers a bit but not by an amount that really mattered here.) The only issue is the Soul Break...
...wait, Cloud's using Holiday Mittens, he can just drop that like Red XIII was anyway, so ok, yeah, Cloud's the obvious choice. Just like Red XIII, Cloud would drop Fenrir Overdrive.
After many failed attempts, I say "fuck it, I have 200 mithril, I can spare one to attempt to master this guy." I get Defense +10% which honestly isn't meaningful, HOWEVER, the carried over Soul Breaks gauge on Terra, Cloud and Auron ARE. Terra now has more flexibility when she can drop either of her Soul Breaks, Auron has a Dragon Fang ready from the outset, and Cloud can drop the MT Attack Up Soul Break earlier in the fight. All this amounts to an eventual success!
Biggest highlight? I actually got to use a Trance Flood + Magitek Missile combo. yes, Terra had 2 Soul Break gauges, and the situation arised that this was ideal. In short, Trance Flood to hurt BS and murder the creepers, then he went Petaflare mode as a result (I think it was his 2nd even), so it did 22k to him. I got to see another boosted Magitek Missile on BS himself, doing 17k total. I have to say, being able to use Trance Flood in some capacity outside of Rubicante was nice since once I got Maduin's Horn I never thought I'd bother, but I had the foresight to think that maybe there'd be an instance where I'd prefer the MT damage over Magitek Missile (especially since overall, Trance Flood hitting 3 enemies is technically over 22x damage, compared to Magitek Missile's 18x, and it does boost Ruinga and Meteor as well so yeah.)
Biggest Derp? Accidentally using Grand Summon I on Yuna when I wanted to use Hymn of the Fayth. Why was that still equipped? Because I was stupid and forgot to remove it. Go 540 damage to all enemies!
