Actually just had great success with teabag string. 5-6 bundled. Already sanitized. I happen to have access to loads of teabags though. That was enough to wick 6 kanger EVOD heads and a few replaceable ego c atomizers.
Be sure you boil any kind of other cotton wick several times,draining and replacing water in between. Waiting on hemp twine. The silica hype made me look for natural alternatives. Stainless worked well for me but, seemed to have negative effects on me.