So far what I'm doing for 4th job Paladin since resets...

Unless you have potential out the ass and hit 1.5m+ on average per blast then HH in most situations is just better especially during wdef up, but if wdef up isn't on and there's only 1 target boss to hit, then HH isn't worth using.

HH is a 3.3 second base cast time, it's 4 times as slow as Blast. So you only need to be able to do 0.25m per Blast for HH to have zero purpose at single bosses outside def up.

Of course, HH multiplies to more targets much better - on Zak's arms it's a nice chunk of damage, same for HT.