For beginners I'd read this:
https://www.e-cigarette-forum.com/f...low-flavor-longevity-and-nic-hit-pt-2.706948/
And Amazon has Cellucotton rayon. The box should have the numbers 44130 on it. Be careful because they also sell cotton.
You wick just a little tighter, it shouldn't be able to pull all the way through the coil easily. You should have to hold the coil to keep from warping it.
About half of the width of Cellucotton will do 1 3mm coil so one piece for dual coils. Sometimes it's a little more or less. Then you cut away everything you don't need. Leaving it there will usually cause some flavor loss. And yes it shrinks a tad but at the same time you don't need to shove it in a port to prevent leaks. In a limitless plus I cut exactly half of it away and it's totally leak proof.
Here's after more use and more power, roughly 170w over the same 2 weeks:
See how I cut about half of it off at the coil?