Nobody can get to 100% DR. It’s multiplicative.
One other comment in case you didn’t see the bug report:
~ Laws of Valor Unstoppable Force Does Not Buff Capt Crimson - #5 by dmkt-1267
There is a bug where A2 does NOT buff toughness until you adjust your gear after casting AC. I discovered this after making the original post.
Kani had conflicting findings, so i looked into it and found you have to unequip, then reequip the Capt Crimson 3-piece set while AC buff is active to obtain the DR bonus from A2. Do this before opening a grift, enter the grift, then port back to town to collect your DR snapshot.
In the bug report, I recommend they should just allow A2 to buff toughness. They should even allow laws of valor to work as well, it’s not game breaking to have a 64% and or 82% DR buff (8 or 9 item requirement) on top of Akkhan’s 50% considering and wiz/barb have rings that grant 80% DR (1 item requirement).