I have 26k health and hit the 30/50/50 and have no issues tanking EC HM 16man. I always make it my goal it keep the 30/50/50 and then see what I can push to gain any more endurance without effecting the others. I pretty much have best in slot I think to what I can get it.
It is 24848 without the Rakata Endurance Stim which tops me up at just over 26k. The stim also gives 54 defence which sends me over 30%.
With that gear set up and stats I have never had issues and even held off Kephesis on 16man HM when he enraged the first time we ever killed him.
On that Mr.Robot link if you click the wish list I have built up the next set of gear that I want to get from patch 1.4 and TFB. Which should top me off around 27485 and still hit the 30/50/50. But with the bad itemization of the new gear it will take a while.