Bray HM Speed run question

[Thaliss]

I only ran as SCH on those speedruns.
Could do as WHM, but when tanks pull that much not sure I would have time to cast Holy.
(could start in cleric stance until we reach the ramp, swiftcast holy , and remove cleric stance?)

Would like advice on WHM how they manage the pulls, just to change a bit from my SCH
On the topic fastest run I had was 2 BLMs that knew what they were doing. Mobs melted in few seconds.