I used up what I had left of my green paracord, and can only guess that the amount used was somewhere between 30 to 40 feet. A 2 foot length for the cord lock/cinch section and the rest is a single strand tied onto the cinch and cow hitched around to the bottom.
I've added a photo collage for starting 'cow hitching'. The last couple of photos are a couple of different starting methods. One is with your cord tied to itself, for a more permanent covering of something like a bottle, and the other is using a separate piece of cord as a drawstring/cinch strap with a cord lock, and then tie onto that piece of cord and start hitching. When you get to working around the bottom of a project, you can switch to half hitching to finish, and sew, melt, or super glue the end strand in place. Just click on the image for a larger version.

*Added to this blog post is another example made with 40 feet of paracord, tied onto the drawstring/cinch cord, that will make a pouch large enough to stretch over a 0.5 liter water bottle, still fits the lantern, and a soda/beer can too .

