once you get the hang of the pattern the size can be adjusted on your own by increasing or decreasing ..there are a few suggestions in the pattern,

using the chunky you need approx 1 and a 1/4 skeins….
using the redheart or worsted weight 4 you have to use 2 strands together and you only need one skein.
i use the center pull and the outer strand together on the same skein and it works nicely for me. but if you want to use to separate skeins and work together thats fine too.
thank you