Our setup was PLD/RDM, SMNx2, BLU/WAR, RDM/DRK, WHM/SCH. It was a long fight, but there was no danger whatsoever. What I found pretty shocking was that blue magic seemed to do normal damage to the Seed Crystal, whereas most other forms of damage seem to have some sort of reduction (e.g. Garuda's Predator Claws for ~700).
A Crystalline Prophecy is annoying. It's kind of like if Zilart Mission was suddenly all the rage and involved camping level 20 mobs around Jeuno. Lots of walking, lots of camping, lots of getting angry at complete strangers. Fun! :D
I'm Magus jubbah-less now, but thankfully, it'll come back from the cleaners on Sunday with a glossy, new +1 on it. I'm still after another Luminian thread and a Flameshun cloth for the Magus keffiyeh +1. It's a really cute healing piece and nice for {Mind Blast}.