Shatterglass should definitely not be an "extra". I think you might want to use an Aegis/Crucible instead of double Eve of Harvest. The reason for this is that Aegis/Crucible provide you with your sustain, but are also more dynamic in that you get a Reflex Block function to your build.

Also, if the enemy team counter-build you with an Aegis, you're dead :) You might want to consider some Shield Piercing. Broken myth might do good, but it doesn't synergise well with Eve. I really suggest a Shatter glass to be in the core build.

I like the idea of stacking eve of harvest since I think that Skaarf should rely on DOT and AOE effects.
But I think your build needs a reflex block against hard gap closing heroes to avoid stuns also while channeling ulti