42 can be very easy or very complicated depending on if you plan things beforehand or not.
Best strategy for the first 2 rooms is having each DD/tank solo a gear while the rest of the party focus on keeping the BLU asleep. It works kinda like the melee version of ODS. And you gotta pull the gears to each corner of the room to avoid AoE from stacking.
The gears spawn in a square formation around the blu so it's easy to pick which gear every melee is gonna kill, but you gotta make sure everyone knows exaclty what gear they are gonna get so they can pull it asap, not doing so will get people killed fast.
After the gears are dead you just kill the BLU, she doesn't have much HP.
The soulflayer is ugly as hell, but it isn't that tough. Plus you have plenty of time for resting to full after each room.
PS > If for some reason Naja picks the BLU to fight instead of a gear it might be best to simply exit the BC and try again.
Edit > For that formation the best would've been having the SMN solo one gear and the RDM go RDM/NIN to keep another gear entertained while the NIN and DRK finished their gears. RDM would also need to back up the WHM and BRD in keeping the BLU asleep.
It would've been kinda messy if the BLU resisted sleeps but it would've worked if the RDM was skilled enough.