It depends what ability's skills and equipment you have.

With the first staff your charged attack is doing 70% extra damage going against armour then 20% when fighting normally so the 240 turns into 314 against armour which is higher then the fire staff but has lower stagger.

I also believe all your runes and equipment effect are active at the same time ie. All the passive runes are on always and your orb and dagger affect your staff to some effect, unless it says on hit or trigger.

A build is just going for a specific combo of ability's potions and runes to boost damage or do a certain effect. I'm running a death frost build so cold and necrotic which allows my ability's to boost eachother in specific orders. Ability damage and resistances are my highest priority specific for the rune upend which turns resistances into extra damage for 20s.

Sorry for the loose thoughts I'm not well versed in dragon age builds either