i did an attempt with a pug raid yesterday, got her to phase3 and around 15% then we wiped and the raid called.

the whelps had like 189k hp... quite hard to die unless all brought to the middle for massive AOE... I played my mage (arcane spec), thruout the first phase my manabar was still good, once the whelps came out, damn i blizzard till OOM because the OT didnt bring the whelps to the centre area.

the fight is pretty much the same, except for the below:
1) guardians join the fight and OT got to tank it, if not killed another one joins in and you will accumulate a lot later
2) whelps had like 189k hp, u cannot split them and aoe them outside their cave. the OT have to bring them to middle where everyone focus their AOE on the whelps. The sooner you down the whelps, the sooner the range can DPS ony in the air and the rest of melee handle the guardians
3) once p3 just a tank and spank and avoiding being feared into caves.

some of my guildies have pugged the 10m and 25m and got the achievement for downing ony in under 5mins...