(Freezing Plasma Blast + HotG) or (Plasma Blast + Hand of Chayula + Wave of Frost)

I am actively leveling my Witch Hunter and it is built to have pretty good burst. Decimating strike with low life damage boost with lucky hit on low life. I seem to kill bosses very quickly because Freezing Plasma Blast freezes the boss so I can get another scatter shot plasma blast out when they are frozen. When they get to 40% hp, they get deleted since I have around 280% attack more. With concentration also slowing bosses attacks in frequency, I think this plasma blast build should do well with bossing, or at least better than other classes for this skill.

What I am wondering is, what would be good weapon swap to have with this build?

I could go mace for HotG when boss is frozen, bursting them closer to 40% life. Downside is I need to be in melee distance and this will take away from casting Plasma Blast if I need to walk to the boss.

Quarterstaff, I could apply freezing mark, cold exposure, etc with hand of chayula. Wave of frost has a high freeze build up so I could apply freezing easier. Lastly, with weapon set nodes and freeze on a skill, I can make freezing last longer.

Lastly, I want to try to add Blasphemy so I could be safer against mobs running at me.

Thoughts regarding QS or Mace? I’d appreciate the advice. I really love all the accessible damage nodes near mercenary.