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Spam Ilgrants instead of Grants because Ilgrants has higher DPS.
Put all compound tech in one subpalette for this quest to avoid wasting time switching.
Use Ilzonde/Safoie/Dash-Jump for fast...

I haven't played other classes but with Phantom Rod, affixes are definitely not important. As I could clear Phanatical Phantoms in 11m49 and Destroyers of Light in 17m36 using Phobos Units from story...