If you want a more accurate answer, diminishing returns kick in right away, meaning that even 1-2% in the node cost more cp then 0-1%, meaning you get less protection from each champion point. In damage taken, since percentages are multiplicative with each other, the more you have of all of them, the less you get from all of them. Like I said though, all my toons have 11% in that node, same as elements defender and then I have 22% into both ironclad and thick-skinned, meaning I lower all damage to me by 33%(well actually less then that, thanks to the multiplicity of percentage damage mitigation). You can put more into one or the other on a per trial basis, all the top players do but I can't be bothered.
Edited by Lightspeedflashb14_ESO on March 17, 2019 9:49AM