So I've been testing out a new Barb BG. Any advice would be appreciated. The main set up I have rn is using the diviners with the guardians. Boost their def with aid and run them with an enchanted platemail basically. Beyond that, C2A Mounted Kinsmen set up with a Guardian and diviner do well too.
You could drop a hammerheart platemail for a mark of redemption, or providence. Also fist of bastion is a great tanking unit to use with those if you can find room for one.