Been a while I played but as far the rune build goes for kench I believe it was:
#Tank Support (standard tank support page)
- Flat Health Regen Quins
- Flat Health Seals
- Flat Armor Marks
- Flat MR Glyphs
#Toplane
- Flat Armor Quins
- Scaling Health Seals
- Flat Attackspeed Marks
- Flat MR Glyphs
#Jungle
Not so sure for this one, in the start of the season tank junglers took attackspeed marks, armor seals and health quins but Tahm really benefits hard from health and recently a lot of people have switched to Armor Quins and Scaling Health Seals. To be honnest you can just use the toplane page. It won't make a hugh different if you have scaling mr glyphs or not.
- Flat Armor Quins
- Scaling Health Seals
- Flat Attackspeed Marks
- Scaling MR Glyphs