Granite and Jade Flasks

I'm beginning to explore these flasks in situations where I need to make an escape from a tight combat situation. I've got a couple of questions:

If I am primarily ES with some EV, is it worthless to use a granite flask? +3000 armour sounds pretty buff, even if its only 0 + 3000 armour.

The jade flask seems pretty hit-or-miss as far as its effectiveness for me, does anyone use these to good advantage?

Any other tips for using flasks are welcome.

Granite + 90%+ Armour is pretty alright. Also Jade has less uses than Granite.

If you have the Iron Reflexes-keystone, popping Jade and Granite will give you double amount of armor.. and if you then use a Quicksilver(or any other potion) with +xx% to armor, it can be futher increased..

Transmute the flasks to increase their armor or evasion. E.g. Granite Flask of Ironskin. Quicksilver Flask of Adrenaline.

Test them in lower level areas by letting a rare mob or low level boss beat on you, then pop the flask and see the effect.

If your.build relies heavily on avoidance, granite flasks have limited utility. Consider quicksilver or quartz instead.