Finally finished my pop for PW.
It's unfortunate, but I was defeated in his final form, I didn't account for the adds spamming aspir, they sucked me dry in moments.
Despite this, I still believe it can be killed solo as Red Mage, you just cannot leave the adds up, they must be killed as soon as possible.
Other than the aspir barrage in the final form, the rest of it is relatively easy. I'll share some notes for any Red Mage interested.
To start, meds/food used:
Echo Drops
Remedies
Vile Elixir/+1
Tavnazian Taco
For the fight, I subbed Dark Knight. This was a good way to deal with all the Chariots as they all (bar Revelation-Chariot) possess annoying TP moves, in particular the 10,000 value Discoid is almost certain death if he decided to use it. I TP'd on the lamps, and weapon-skilled the Chariot, in addition to Absorbing PW's TP whenever I could and maintaining Stoneskin to lessen TP feed. This method took 4 Requiscats per Chariot (in a near optimal set for Red Mage)
Once each form is defeated, he'll despawn back into Dvergr form, and use Crackle, then Hellsnap before changing into his new form. Have full resist set on for Crackle, the Magic Defense Down is potentially dangerous. Soon as he finishes Crackle, cast Stoneskin, in a decent set you will finish cast and be back in resist/TP set before Hellsnap, not that it really matters for hellsnap anyway. Just be ready for the next form.
The effective use of bar spells per form is recommended:
Chariots; Barparalyze/Barblizzard - Max Paralyze resistance.
Medusa: Barstona/Barpetrify - Max Petrify resistance
Gurfurlur: Barblizzard/Barpetrify - Resistance against his Petrify/Paralyze moves.
Gulool Ja Ja - Baraero/Barsilence - Max resistance against his adds casting silence on you.
Cerberus - Barfire/Barparalyze - For the paralyze/fire abilities.
Khimaira - This depends on where you care to fight him. I wasn't sure if he turns, so I went under the assumption he does. Barstona/Barpetrify - Max resistance against Petrify Breath.
Hydra - Same with Khimaira, depends where you fight him. Again, I went under the assumption he turns for breaths. Barfire/Barparalyze - Resistance against plague and paralyze breath respectively.
On Hydra in particular, maintain stoneskin as well as you can, and kill him as fast as possible. It could be brutal if any of the Dahaks use Full-dispel on you.
Sets used are on my profile, best of luck to anyone who attempts this, it's quite a nice challenge for Red Mage in today's FFXI.