Just wondering if any DC arties out there use tactical detonation or prismatic strike in the level 28+ EE quests, and if so, what are your DCs on those spells to make them effective?

I haven't played an artificer in about 2 years, but they were pretty fun and versatile. After I get completionist I was thinking of being some sort of DC caster and sticking with it for good. It'd be nice if those arty spells worked in the upper EEs.