Percent HP runes on tank junglers.

I was wondering, percent hp runes vs scaling on full tanks? I believe bonus hp from cinderhulk is added first and then the total hp + total hp *.09 = health total. What also is unknown to me, is how SOTA interacts with cinderhulk and percent health runes. I just played a game with mundo in top lane running percent health runes. with Spirit Visage, Sunfire Cape and SOTA at 160, i had about 2.8k hp. SOTA fully stacked, giants belt, ruby crystal added and idk how many levels later, before i had completed my 3rd hp item, i was sitting at 4030 hp. Are the runes worth it?