I put defense augments instead in my gear.
Use: Defense / Proc: Absorb
Shield 45% (No ward)
I did something similar but went almost full defense and some absorb augments.
Use: Campaign Relic of Imperiling Serenity (+ defense on use)
Stats: Battlemaster's Relic of Imperiling Serenity (+103 defense, augmented so +121 defense)
Completely unbuffed from memory I have about
22103 Health (24k buffed with stim)
38% Mitigation (Just under 6k armor)
31% defense (Over 500 rating, something like 525?)
40% Shield (55% with Dark Ward)
I just got the black hole chest piece so I gained some defense and lost absorb making my stat balance wonky right now.
They way I understand it, I'm at the caps for Absorb (50%) and Defense (30%) already based on this forum post for tanking.
I'm waiting until I've bought all the black hole gear to re-augment as the stats balance is definitely going to change, but it might be time to go for HP? I'm not sure. Can anyone confirm if those are truly the caps?