Not sure what the right diameter is for your application but check out Top Studio. They do amazing detail sets for cars/bikes.
Here's a link to some braided lines down to .6mm
http://www.topstudiohobby.com/index.php?route=product/search&filter_name=braided
Thank you for this I checked them out and from what I can gather you can't buy from them directly... And they only have 2 UK stickisys and they are all sold out... I will keep my eye on it.. Thanks again..