Tanks, please use buffs

[technole]

Holy Spirit consumes a massive amount of pld's mp and can proc 3-4 times before mp gone.
Sheltron is not a free use at will but depends on your oath gauge and kills half of it when used.
Requiescat's potency decreases with MP (mp is the thing you're burning with Holy Spirit).
Hallowed is more an emergency utility than a feature to use when available, but your suggested use is good if you're confident your party is good too. I'll not do it with PUGs.

Only bad tanks think hallowed is an emergency cooldown, it's a planned cooldown. Even in end-game savage, you have to plan to use it for certain mechanics like back in A12S or even now in O4S. This goes all the way back to Coil days, there are only so many cooldowns you have up for the duration of such a fight, and Hallowed Ground is one of the options that must be used.

Holy Sprit builds your Oath gauge, which in-turn allows Sheltron procs. I was spamming that Sheltron procs in Bardam's like it was no one's business. There is no excuse not to use the skill at-will, it's very potent. MP management just becomes an issue if you have to plan an Oath change.