Here are some HP Ice on Kojondo calcs:
Salamence, 0 HP / 0 SDef: 73.7% - 87% May OHKO after SR damage
Ononokusu, 0 HP / 0 SDef: 41.1% - 48.3% May 2HKO after SR damage
Sazando, 0 HP / 0 SDef: 33.8% - 39.9% 3HKOIt... doesn't look overly useful for Sazando. I'd say Speed > SAtk EVs, in general.Salamence, 0 HP / 0 SDef: 70.1% - 83.4% May OHKO after SR damage
Ononokusu, 0 HP / 0 SDef: 39.3% - 46.5% 2-3HKO (after SR damage)
Sazando, 0 HP / 0 SDef: 32% - 38.1% 3HKO with SR damage
Why would you use HP Ice on Ononokusu or Sazando? You can OHKO both with High Jump Kick.