Does the critical bonuses from the Sanguine items and the Wheel of Destiny stack or is it percentage of top of percentage?

Question

For example the Eternal Winter  bonus: 8% Critical Extra Damage from the Sanguine Galoshes (Avatar of Nature -> -900s cooldown, Terra Wave -> +8% critical extra damage, Eternal Winter -> +8% critical extra damage) and the 8% Critical Extra Damage bonus from the Gem Atelier. I am getting 16% Critical Extra Damage on my spell?

Answer 1

Yes.

Basic powerful critical is 10% chance to deal extra 50% damage,

By adding more modifiers (8% from wheel, 8 % from item) you make this extra 66% (instead of original 50%)

Possible way to "multiply" the effect is by using lowblow charm which increases the chance to trigger the critical hit from 10% to 18%. It wont affect the damage done, but multiply the amount of critical hits you do.

If you are not using low blow, having "extra damage done" might actually gives you more damage in a long run compared to increased critical hit. iam unfortunately unable to calculate it without knowing precise formula