Flat Health or Scaling Health Yellows on Tank support?
I guess it depends on how much early game harass you plan on taking... Thoughts and opinions?
PS- For champs such as 
3 Comments
Flat Health gives you 39 additional HP over the scaling runes at level 1. At level 2 (perhaps the most common "all in" level for bot lane) the difference is 28 HP.
If my math is right, that lets you tank one additional auto attack.
Scaling Health surpasses Flat Health at Level 5, and goes on to become more than three times as effective at level 18. I know that damages are higher late game, but I'd still go with the scaling.
Every pro I've seen uses flat health...then again...none of us are pros.
Honestly, I'll typically just take scaling armor in seals on tank supports. You get quite a bit of early health from Targon's Brace and Sightstone, so the armor helps.