Stoneskin modifier

Hi I have the following question about whm

1. How much dmage will stoneskin mitigate, in general?

2. Doea it matter the class / job tht cast the stoneskin? I.e is the stoneskin cast by whm stronger than that of pld? who cast the stronger stoneskin - whm or sch?

3. What is the stat modifier for stoneskin? If whm/sch has cleric stance on, will the stoneskin be as strong?

thanks

whm, has the graniteskin trait which increases the amoutn to 18% from 10%. it provides a damage shield based on the hp percentages i mentioned.

There is no modifier other than the target's HP and the Conjurer trait. WHM gets the stronger version because of that but every SCH should have it equipped anyway.