Skill gem use questions

I'm currently running Ice Crash - Fortify - Blood Magic - Hypothermia in a corrupted RRRG Bringer of Rain, but I've just upgraded from Cameria's Maul to a rare axe with mostly phys and a bit of fire damage (and lightning resist, for what that's worth).

Even before, I didn't have any means of chilling enemies for hypothermia other than Arctic Armour's trail and the actual cold damage in the hit itself, which has now gone down about 15% per hit (Resolute Technique is in play, so no crits).

My build can be summed up as high life, block-spellblock-endurance charge melee phys with barbarism notable, arctic armour and purity of ice/lightning. I don't have any elemental damage bonus on the tree and gems.

So now I question my Ice Crash, Hypothermia and to a lesser extent Arctic Armour gems.

Especially since I lack a Vaal skill and it would be mucho useful with my low damage.

Should I replace Hypothermia with Vaal Cyclone (or Vaal Spectral Throw)?
Should I instead run Cyclone (much lower tooltip dmg) and Vaal Groundslam(since I have one)?

If I choose Cyclone, should I then replace Arctic Armour with something else since I won't ever get the stationary mitigation bonus on Arctic Armour?

Fortify and Blood Magic on my main setup are pretty much mandatory at this point, so if I ditch Hypothermia the normal and vaal skill need to be one red one green.