Id say you probably never want to stack rampart and vengeance

Vengeance is 30 percent and youll probably get a heal toss when a tb is coming anyways

Between pulls i cycle between vengeance/ir spam in deliverance (you can defiance if youre worried but you have ToB and conva if you need them anyways so itd only be for ss healing)
And rampart/ unleash overpower spam while the other set cools off

Once you hit 70 and get decent gear its all youll need for pulls really. The rest will be boss mit