When healing a WAR, i like to put stone skin & regen, then switch to cleric stance and DPS a bit (when the fight isn't too dammage intensive).

If you have time when DPSing, placing a stone skin once in a while is usually good, and don't forget to use Shroud of Saints when you are à 3/4 of mana (1/4 used)

If you use Shroud correctly in speed running, you won't be OoM for a long while (maybe never if mobs die fast enough) even when abusing Holy. You run to the pack, Holy 4-5 time, Shroud (and remove Aggro ^^) and continue to next target.