I’ve used the Kartopu Zambak yarn as second color yarn. For my first color yarn I don’t have the info but it is a DK yarn.
You can change the size by changing the size of the needles.
And you can change the height of the hat by knitting more or less repeats of the pattern in height before starting the crown, this way you can have a normal beanie, or a slouchy one.
I did 1.5 repeats of the pattern in height and I used ~35g of each color yarn, so ~75g total.