From 265 - 300, it should work OK.
Runecloth Belts will generally DE into Dream Dust, and occasionally Eternal Essences.
Shield - Greater Stamina only uses Dream Dust. That enchant should take you from 266 - 290.
Then, you'll use the Eternal Essence that you also got (albeit a lesser amount of) to go from 291 - 300.
Does that make sense?
However, you will want Nether Essence from 240-265. I missed that part. DOH!! Nice catch. My recommendation, since you are already at 253, is the
Black Mageweave Headband. Those will DE into Dream Dust and Greater Nether Essences. It should get you to 265.
For some quick mageweave, Jintha'alor in Hinterlands is an easy farm. Just clear the whole area out, and you'll get many many stacks fast.
I'll update the guide. Sorry about that.