What i usually go is Primary, Domination: Dark Harvest, Sudden Impact, Eyeball Collector, and Ravenous Hunter. Secondary, Resolve: Conditioning, Revitalize. then Adaptive force (+9), Adaptive force (+9), and Health (+15-90)
The reason i go dark harvest is because it is extremely helpful for his late game and makes him able to have a large impact on late game team fights because of the impressive burst damage gained through him stacking up his dark harvest, also if you get a kill soon after you proc your dark harvest its cooldown will be reduced too 1.5 seconds instead of 45 seconds which allows you to get another stack sooner.
(Note: you will have to roam a bit if you want your dark harvest to be most effective for late game)
These are the summoner spells I use when playing him:

Also my build is usually this (buy items in order from left to right):
then buy this after you get full build 
(Also if you dont think this is reliable just check my match history with me using the runes, also I have a lot of experience playing this champion and I am Mastery 7 with about 280,000 Mastery on him)