A 25 foot length was used for the one in a 'whipping' pattern on the aluminum water bottle. And a 40 foot length was used in a woven pattern on the white stainless steel water bottle.
Both started off with coiling the cord around the bottles, with the starting end just held in place with a rubber band and later tucked to finish.
The 'whipping'(snaking) version, an example is seen in Geoffrey Budworth's 'The Complete Book of Knots', is easily zigzagged and looped around a couple of coils on each end of the paracord coiled wraps, and tucked to finish.
The woven version resembles 'grafting' type knot work, as seen in Stuart Grainger's 'Creative Ropecraft', but is instead a single length of cord. After coiling the cord around the bottle, one end is then worked in an over/under pattern, back up then down, all the way around the bottle. For this pattern, I went under three coils, over three coils, but like 'grafting', you can vary the pattern to your own tastes.
I used a Perma-Lok Jumbo Lacing Needle to feed the paracord over/under as I worked, as well as a pair of hemostats/forceps.
Here's a woven paracord can koozie, done with a 25 foot length of cord. The weaving is just like that done on the water bottle, but with the vertical over/under part done closer together for a tighter weave before changing to half hitching on the bottom.