I finally found info on how spell penetration works, and made a simple "infographic" on Desmos! https://www.desmos.com/calculator/bqaac6rtnq : r/elderscrollsonline
Skill Calculator Archives - ESO Life
Crit Damage and Penetration — skinnycheeks.gg
ESO Arcanist Class Revealed in Full - ESO Hub - Elder Scrolls Online
WIP: Skill Calculator for ESO : r/elderscrollsonline