i would advise against using these types of relics. its better to go with the PvP ones.
not just opinion either mathematicaly they are better.
Tanking involves covering situationals not just constants. PvP ones are great for mean mitigation, but clicky relics give you more 'on demand' mitigation when you need it.
IE when fighting Toth and Zorn:
-113 Defense relic is useless while you are on Zorn.
- 315 Defense every other time you are on Toth is great.
Same holds true for SC/FB, Kephess, Writhing Horror and Fabricator. Depending on your strat it can also hold true for many other fights including Vorgath (thats now all of EC HM), Gharj and Annihilation Droid. I'm not sure about TFB HM yet, we're still working on it.