On my spellsword character im thinking of going with light for one reason, i love the forsworn armour, but is it a really bad choice,should i just go for heavy armour? thanks...

Well, they used meduim in Morrowind and Heavy in Oblivion, but the NPC SPellswords use light armor*. I think you should just chose based on which you like better.

*In Skyrim

I used forsowrn armor until level 35 on expert difficulty, so i think youll be fine as long as you get your smithing up. OH and enchnating. And aalchemy wouldnt hurt either with those fortify so and so potions.

I've tried it both ways, and i feel light armor buffed with armor spells works better.

Light armour, then you can wear some of the powerful masks and yet still get the bonuses from the all-light-armour perks. You can hit the armour cap in light so no worries there. Also I imagine you'll not be putting so much into stamina and therefore won't be able to carry as much, so the lower carry weight of light is a huge bonus.

I tried full Heavy armour but I felt to much like a tank rather then a swordsmen, so I dropped the heavy armour apart from the boots and gauntlets and now I wear a robe.