Hmm. Our LS did a
Soboro Sukehiro run recently; 4/6 drop rate. Or, as one member pointed out, 100% drop rate when we managed to stun
Unstable Cluster's Self-Destruct.
We had two PLD tanks, three stun'ers (BLMx2 + DRK), two WHM's. BRD, COR and RDM for support, too, along with a bunch of DD's. (Fourteen player alliance.) DRG parsed to be top DD, even with dead wyvern half of the time. RNG and SAM were pretty good, too.
I would be hesitant about solo tanking this; it hits hard, and can take out a huge chunk of the HP bar fairly quickly. With the lag from the alliance, timing self curing was hard when the Unstable Cluster was in my face. More skillful PLD's with less laggy computer may be able to solo tank, though.
BTW, the normal clusters around the cave can drop a good number of
Clustered_Tars; it's worth it to bring a THF--we went with five Clustered Tars, and came away with four Sorobo Sukehiro and
SIX Clustered Tars.