The way my Argonian Mage is, is that i spend 1 level in Health for every 3 levels in Magicka. At Lvl 81, he'd have 300 Health/700 Magicka base then, which would be enough health to allow him to survive an Ancient Dragon's bite with Ebony Flesh or Dragon Hide up. I use all schools of magic quite frequently on him. I of course use Destruction for damage, but i also use Restoration for Grand Healing/Heal Other for my Follower/Dog, Illusion for Call to Arms to buff my Follower/Dog/Summons, Conjuration for Soul Trap and dual Dremora Lords/Storm Atronachs, and Alteration for Ebony Flesh/Dragon Hide and Transmute.

His Robe is the Archmage's Robe, his Gold Ruby Circlet has Fortify Magicka/Fortify Magicka Regen, his Gold Diamond Necklace has Fortify Magicka/Fortify Destruction, his Gold Diamond Ring has Fortify Magicka/Fortify Magicka Regen, his Thalmor Gloves has Fortify Magicka/Fortify Carry Weight, his Thalmor Boots has Resist Shock/Resist Fire.

Here's his planned build. http://skyrimcalculator.com/#77264

Interesting your build is pretty close to mine, on what difficulty do you play and what level is your character currently? I'd like to believe that 300 health with a fully perked Ebony Flesh/Dragon Hide would help considerably with getting one-shot by the more common enemies on Expert/Master, but reaching level 81 could be a problem for a lot of people, so they might not actually see that much health on their character while using those ratios. And of course there is the "you should never get hit" argument in which case investing in health would be a waste.

My mage is currently level 22, playing on Adept, with base 100 health and a Fortify Health ring bringing it to 120. So far I haven't been one-shot by anything, but bandit chiefs can kill me very quickly if I don't have room to maneuver.