If I play a mage in mages clothes (NOT in light/heavy armor). And use a meatshield as a defense. Will this suffice? Or am I asking for trouble with this play style? Would it simply be better if I just drop the whole conjure meatshield thing and stick to light/heavy armor for defense?

You will have to get the Mage Armor perk that gives you armour for wearing clothing.

I get along just fine with using companions and summons as my faithful armour.

Yeah if you go conjuration you'll be fine.

That's what I do. I also suggest having a follower like Lydia

You must realize that you are the dragonborn, the one written about in the scrolls and at the same time the writer of the very same scrolls, time itself is for you to command. You are the one profecies speak of, the dreamer, the realizer, the doer. Reality itself will bend to your will and nothing will be impossible or possible.Everything and nothing is in your grasp, nothing being everything and everything being inconsequential. The only thing that matters is what you realise or do not realise, you write the the rules, read them, live them or die by them. Again and again and again.