My current character is a mage with a similar built so I can share my experiance:
First of all I don't use a mod that changes magica regeneration so it's important to know how to keep magica flowing if You take the Atronach as birthsign. My mage is a conjurer and can tap his summons, Alchemy is also an option. Get to know where all the shrines are to make good use of the restoration blessing.
You chose Unarmoured so You want to play a true mage without armour, just clothes. I also tried that, but there are so many nice enchanted armour pieces and You loose slots for enchantments. I made a compromis for me and don't use helmets, armoured gloves and pauldrons and anything that stucks out of the robes.
You will have some trouble to rise Your endurance and it will be difficult for You to win mele fights with no armour and few health-points. You will have to use paid trainers, something I try to avoid. I changed Long Blade for Blunt Weapons so I can use staves. I remember Gandalf always carrying a staff, althoug he also carries a sword, so it would be an option. There are not many good staves in the game but You can enchant Your own. A staff/spell of paralyzation helps to despatch an enemy when wearing no armour.
It's very rewarding to play a mage in MW if You play him right. As You never have played one before I can tell You to play him different: do everything like a mage would do it. Be smart and inventive...
? My character collects soul gems of all remarkable enemies he had to kill.
? He creates difficult spells with fancy names
? Sometimes he avoids fights by levitating away, making himself invisible, calming (deluding), paralyzing but more often he uses his summons to do the dirty job