I got some questions, bout the dk igneous shield, can it be stronger, with more magicka or stamina, on me and others? O lr when I have more armor or defense, does it get stronger on me and others? Is there a way to make it stronger?

If I use igneous shield, with the undaunted bone shield and magna ultimate skill or harness magicka shield? How does that works? Does it stacks? Strongest shield only or last cast shield?