You will actually find every answer to your questions in my beginner’s guide, with the exception of how to spec ring of shields.
For speccing Ring of Shields, I would take the nodes which grant you extra shields and to increase the time the shields are active. Take Reinforcement 2/2, Amass 3/3 and Enduring Defense 3/3
Yes it’s a stat stick. No it does not use weapon damage . Increase physical damage % and increase crit chance % are the 2 prefixes I use on my weapon as they both increase hammer damage.
Have you tried Shield Rush? I like it a bit more that Lunge because it can be used to escape because it does not need to be targeted at an enemy. Also you can use the Shield Rush to travel faster. You can rush infinitely until you hit an obstacle or release the button.
Volatile Reversal is no skill for me. I don’t get it timed right. It is 50/50 I end up with less mana than before and be teleported right back into the pack of enemies I just evaded.